Small website for payment processing

We need a very simple, 1-2 page website through which users purchase credits using credit/debit cards. How it should work from a user's perspective: 1. User logs in using an account number . Accounts must be valid but no password required (Account numbers are stored in our MySQL database). 2. User types-in a purchase amount and presses a "purchase" button, at which point a 3rd party payment processing system takes over while our website waits for a reply. No financial information should be stored or communicated from our website. 3. Depending on the reply from the transaction, an entry is written to the database, and feedback is given to the user. That is essentially it! There's no shopping cart or shipping. Deliverables: 1. A list of 3-4 potential 3rd party payment systems (such as Beanstream) and a brief description and recommendation of which to use. We need to know the fees/costs and payment processing rates. Important note: The 3rd oayment system MUST support INTERAC cards (using INTERAC Online) in addition to the standard credit cards. 2. The website as described above using HTML/PHP/Javascript/AJAX only. The source code must be in a private online source code control environment that uses Subversion for access. We do not mind paying a small service fee for such an environment. Future projects: We have other web development needs. So if we're happy with your work, we may get you more involved with some of our present and future IT systems. Candidates: -Proficient in PHP/Javascript/AJAX -Proficient with Linux, subversion and source code control -Have a portfolio of develpment work (prior development of payment systems is preffered)