I have a 5750 that gets 170+/- Mh/s on pci-e 2.0. You can pick up a molex to 6pin plug that will provide the power just fine.
Thanks!!! thats what I needed to know
Glad I could help, have you signed up at Coinbase yet? Check out the link in my sig to get 0.1
BTC for free

EDIT: Yup, should be more than enough.