PHP paypal system on a forum.(repost)

Hi, i'm looking for someone to build me a new paypal system. Basically I have a booking forum for a mobile disco and clients need to pay the deposit. When theu have filled out the booking forum they click a paypal pay now button. This then take them to paypal and they pays come back to the website to page [login to view URL] this should then to what need to be done in the database to how on the admin page that the payment has being made if it fails it will tka them to fpayment.php. There is a system in place but it has stopped working. it does what i have said but not no more PLEASE NOTE I WILL NEED A FAST START AS NEED THIS FIXED ASAP