Search engine required

Hi, I need to get a search engine developed, with certain functionality 1) user will be able to submit their website, just as they do in Google, 2) site will be searched in random order according to the keywords 3) Site will be searched from our database only 4) First four position should our control of either making it paid search or leave it as normal search, 5) If we make paid ads it should have the option for the admin to control the amount of duration it will be displayed, if somebody books the first position for 3 hrs display then it should set it for 3 hrs and then it should automatically digrade to normal ad, 6) It should have the option of advance booking, like if all the positions are booked for 3 hrs, then one should have the option of booking the adds after the current ads, and that ad should come by default after current ads expires 7) Admin should have the option of controlling the time limits of ads 8) User should be able to pay through, credit cards, cheque. 10) Interface will be just like google that is only search box, 11) User will only be able to search by keywords. 12) We may have the option of advance search