I'm using bitcoin since a month, and I still give the community my GPU power but I think it isn't very profitable because I can give you only 8,3Mhash 
Maybe you should use a different GPU.hey,
thats the fact, I don't have a better gpu or something like that.
In near future I want to setup my pc with a sever OS and host a small, secure, anonyme webside. With the same pc I want to mine for bitcoin, but I have to buy a new gpu and so one.
If I understand bitcoin right, the whole transaction can only run, if the network has power. If I can spend the network power with my old or maybe a new gpu the community benefits from that or what do you think?
tm