How about run it as a raffle as someone has already said. Dizzy, Daisy and Donna (hope i got that right, i know there were a few more involved) ran a charity raffle a few weeks ago on the Q&A forum and raised a huge amount.

Sell the tickets at between £3-£5 each, and that way it can be open to anyone, and more people are likely to enter. You can enter once if you cant spare much or buy a few more if you can.

Would raise more this way in the long term I think and everyone could contribute.