$238 + shipping for a decent loop. Won't break the bank, isn't top of the line but isn't too bad either. Pay $30 more for the block and you can get the Apogee XT. Since you'd already be almost $250, you may as well get the top of the line block.
Yea, that pump could handle a GPU addition no problem. Just make sure the rad is up for the job. I've got the XT, MCR320 and an MCW60 (GPU block) in one loop and it's just fine. Had a NB block as well on my older board, but the CPU wasn't as much of a furnace either. I'm pushing it with a GPU and an i7 on this MCR320. You should be ok with a single-core GPU later on, the Phenoms aren't quite this hot.