Student Information System (Attendance / Billing)

We need a new Student Information System for our charity theatre group. At present we use OpenSIS ( ) however it does have a few bugs, isnt really focussed on the UK, and costs way too much to add billing and discipline modules. So, we would like someone to either: 1. Create their own modules to addon to OpenSIS so that we can set invoices and payment up per student or in bulk (see demo on their website) and discipline (again look at the demo on thier website and this is what we would like) or 2. Create an entirely new Student Information System for us. Not too worried about the script language - we will be running it off Windows Server. It needs to be able to let us enter student details and store them (full list will be provided to winning bidder), needs a teacher access section where they can mark attendance and also comment on any bad behaviour, and a billing section where we can mark in when any payment are recieved and query when they havent. If you are familiar with them we are looking for something along the lines of SIMS or Serco but in PHP reduced form, Any questions please ask, Also please note we are a charity group and dont have big money to throw at this. This isnt said to keep the price down, this is said because if you bid too high we simply cant afford the costs.