Check website for possible security breach or problems

I have a website [login to view URL], I’m looking for any possible problems with the site that may be affecting my sales. My stats show good solid hits and visits with potential buyers, but conversions do not seem to be at the same rate as in the past. It seems like there may actually be a problem somewhere. I need a professional to look over the site for any breaches or problems that may be causing issues with my conversions. Any significant findings that result in a substantial increase in sales will be rewarded with a very nice bonus. Please look over my site and let me know what you can do to help. Thank you, Dana