Need purchasing advice

I was looking around on different computers,( i don't have the time/willingness to learn how to build one ),and I because i get a pretty hefty discount on hp computers through my work i was thinking about getting this one:
http://www.shopping.hp.com/webapp/sh...HPE110t_series

It's a customizable build,and i was going to upgrade it to 6 gig ddr3 ,and maybe upgrade to a terabyte of storage.I play several mmo's, but nothing thats top end. The 4650 should be enough to handle the main mmo im on right now (WoW) on high settings.
But anyway, the thing i was worried about is that this system only comes with 350 watt power supply, which seems kinda low, will it be able to handle the machine without problems(I think the 4650 needs a lil more then that). It doesnt offer any upgrades, or i would.
Any reccomendations on what i should change around ect would also be appreciated, just remember i'm restricted to this site because of the huge discount I'll get through them lol.XD

Looking at my magical GPU power chart, it looks like a 7300LE uses on average 10-20W(max) while a 4650 uses 30-40W(max). So, the 4650 will use a bit more power, but not much more, and the rest of the system is fairly low power. So, assuming that is at least a mediocre 300W PSU and it is in good working order (not too old) I think that should work fine.

Thanks a lot for the help and quick response, I'm always a little cynical when buying something like this so it's good to hear.

I'd personally get this one instead:
http://www.shopping.hp.com/webapp/sh.../e9300z_series
You'll save $100 and you won't notice a huge slow down in apps or games.
Benchmark to prove my point:
http://www.anandtech.com/bench/default.aspx?p=106&p2=52
Like Bryan said, the 4650 will run on that PSU, it's proven to work on crappy Dell PSUs and the 300W HP PSUs.