Re: Upgrading opinions
Don't go overboard on the power supply because they'll draw more than what you are using so 450-500 watts should cover it well. As to the 7770 it's a good card but meets bare minimum for gaming so it'll do on medium res and some on high depending on the games.
Do go for quality PSUs as they provide ample amperage on the rails. My fav is Seasonic and is well regarded.
I yam what I yam