Computer Upgrades! I am clueless! :|

[Lucca]

Okay folks. You are hopefully pretty techie and it is time to upgrade my computer...but unfortunately I'm rather retarded in this area and I need some sound advice! :)

Here's some specs on my computer:
http://www.tigerdirect.com/applications/searchtools/item-detailsInactive.asp?Sku=C67-1348

But to go into more detail than what's there: There's about 2 extra slots where I could stick extra hard drives/CD-ROMs, my video card is AGP and comparible to an Radieon 9600 (2004 edition), and my power supply SUCKS. It's only 350 watts.

So here's the deal: this week my OS utterly borked on me and my vgaoem.fon file got corrupted. Since I have the OEM version of Windows Media center and gateway restricts the hell out of EVERYTHING regarding repair, it's currently in a shop getting data saved/OS reinstalled. THe tech guy told me though that my power supply sucks for what I have, and I should look into possibly getting a back up hard drive (which I've been considering for a while anyway).

So here's what I'm looking for. I've trolled Tigerdirect and Newegg but a lot of this gabblygook. I'd rather not spend more than 250-300$ for this stuff (otherwise I might as well just buy a new computer). My knowledge of installing stuff is pretty nil too, so I'll probably have to pay a guy to install all this crap.

I need:

*A new power supply. I'd like 550watts/volts/whatever but I can live with 500.
*A hard drive. I'm looking at a WD 320 gig cavier Hard drive that seems fairly cheap and nice for what it is (Plus I have the same kind of hard drive as my external USB drive), unless there's a better drive out there, or a better price.
*Ram! I'm looking to upgrade my ram to a gig or so. I've heard Corsair is good, but IS IT? :O
*This is more optional, but video cards baffle me. I'm not looking for a HUGE improvement but what's a good card (that also has a TV tuner?)

Thanks, 'Fan people you! I'd appreciate the help. :)

[Rico]

I'd suggest an Antec power supply.  There's a lot of quality differences between PSes of the same wattage, and it's really not a component to skip on.  Any of the 'big' names should be fine, but Antec I'm immediately familiar with.

Corsair's fine RAM, and the hard drive looks good if you get a bigger PS.

The Radeon x1600 XT and x1800 GTO are both solid mid-range cards.  I used to use Radeon All in Wonders for good video cards with TV Tuners, but they're awkward to upgrade.  You might think about just getting a separate TV Tuner to go along with it; I've heard decent things about Hauppage external tuners, though I have no personal experience.