PHP Photo Gallery Update

Project Description:
I need someone to do some work on http://www.focusu.com, an image hosting/sharing site which I designed. Unfortunatly my php skills are lacking so I need some outside help =)

The site is running on my own dedicated server running on WHM/Cpanel, so I can give you access to the server if you need to install any software or do any configuring.
The site comprises of 2 main PHP scripts.

The gallery:

The gallery runs on a script called Albinator, the Albinator site is at http://www.albinator.com. The developers have now discontinued the product due to a company fall apart as far as I can tell. I have modified a large portion of the code and heavily modified the templates etc.

The forum:

The forum is running on vbulletin 3.0.6 and is pretty much as bought besides the template modification on my part. You will notice it has a different domain name to the gallery, this is just a parked domain and both scripts are on the same server acct.
Both scripts are running in the same SQL database and you can access through myphpadmin or ssh, or any other method you know of =)
Ok that's the background info so here's what I'd like done in order of priority.


1) Credit Cart Payment System:

I would like a credit card payment system to be implemented into the gallery so users can upgrade/downgrade/cancel there memberships though a user acct interface on the site. The only problem I can see is downgrading accounts which have a large amount of media in them to an account which can't hold that media. A possible solution I can think of is to not allow them to downgrade there account until they have deleted a sufficient number of photos.
Also the ability to use Paypal as well as a credit card would be a bonus, there is currently a Paypal system for the gallery but its not functional.
One thing I would like to do in the future is also allow members to sell there photo's and print photo's etc, so it would be important to choose a payment system that could possibly support this if ever implemented.


2) Forum and gallery integration:

Currently a user must create an account in the gallery, and then create another account in the forum, and then subsequently log into each separately which restricts the flow of the site. If possible I would like the databases to be linked or merged so when a member registers in the gallery they will automatically be registered in the forum and share the same login cookie.
I would like the gallery account creation to be made the primary and have the forum account creation page link to the gallery one, this way a user may only create an account through the gallery and will cut down on confusion. In this case the gallery account creation page will need to have the necessary extra fields added to satisfy the forum account creation requirements. (that's just my idea of how to do it, if you have a better one let me know)


3) Extended private messaging system:

Extend the private messaging system from the forum into the gallery, so a user for example could view a photo and then send the author a private message.. this should be quite easy if it's possible to integrate the gallery and forum.


4) Improved comments system:

Lastly when you view a photo in the gallery there's a comments section at the bottom of the page where a user can leave a comment about the photo. I've had a bunch of complaints from people that they don't know when someone's left a comment. So I would like the system to send out an email to notify the author that someone has posted a comment etc (if possible allowing the user to select somehow to not receive emails, this could be in the settings page or possibly an option for each individual gallery). Not quite sure of the best way of doing this, but basically just some way of keeping the users talking and coming back to the site =)


5) Image Direct Linking Bandwidth:

Lastly I need some bandwidth limitation implemented, Basically, I want users who pay a subscription to have unlimited bandwidth, and users who are using the free account to have say 1 or 2 gigs bandwidth per month when they direct link. i.e. if they post a picture they hosted on FocusU on another sites forum id like that image to be replaced with my out of bandwidth add when it has been viewed too many times and they have used up there bandwidth.

That's about my whole wish list for now.

Also a couple of things I would need to have guaranteed.

1)You wont wipe the gallery user database (very important as there are currently almost 800 members registered)

2)You wont *break the site* (this is my baby =)

Thanks for your time! If you interested in doing this please bid =)