The strange thing is that it was on that amount of blocks even when I first installed it
so you upgraded then from a v3.x version, right?
downloading the blockchain now would result in my wallet being corrupted and my money being lost
as long as you keep a good backup of your wallet.dat, you will not lose the ability to spend those coins.
you can force a more recent snapshot of the blockchain here:
http://sourceforge.net/projects/bitcoin/files/Bitcoin/blockchain perhaps a clean copy of the blockchain will resolve the problem stopping the client from downloading the blocks. try -rescan if necessary.