Have you tried going to one of the online freelance markets to get it cusotm built for you? You should be able to find a coder that will produce that script for $300, the places to go would be:

• http://www.eurofreelancer.com - cheapest in terms of commissions
  http://www.getafreelancer.com - quite busy, can be unreliable
  http://www.getacoder.com - not sure

Good luck!

M