Booking & Payment cgi script

I run a site that books stalls at events and I require extra features added to my CMS software (cgi); my current CMS already has PayPal instigated so I want to use that as payment. I am looking for the following features added: 1. Booking system that will allow my members to select a stall and pay. Members to select a stall either from an image or using a dropdown menu/list; once selected they will be asked to make payment via PayPal. Once payment has been made then the stall list will only display what’s available to other members. 2. Calendar system that will allow me as admin to place events for the members to select which event they wish to attend and book, plus allow the non-members to search (public area) for up and coming events using dates, location and keywords. Sadly I require this script very soon and can only pay $170 OVNO as we are a non-profit site. Thank you for taken the time in reading this.