That's not too bad. I'd say go for it. Just make sure your PSU will be able to handle the upgrade. If you're not sure if it can, post the model name here and I can answer that for you.
I'm not sure if I would trust that PSU with your new card. The 475W got a pretty bad review from hardware secrets and your 625W version will be no better. It can actually output a max of 575W. Poor 12V regulation and DC output caused their test system to behave erratically and there's a chance the same thing will happen to your system.