Paypal Mod for usergroups

[yellows]

Here is what i am aiming for : -

- User signs up via buy ity now button or something simular
- user signs up with gallery and that username is given usergroup with time scale as stated in when they signed up


it is for http://www.sexymalecelebs.co.uk/payment.php basically users get granted access to the videos for 1/2 years or lifetime and the timings are set manually, just want to do this automatic and if possible user creates account in same process or username created automatic.

Let me know if anything like this is possible

James