Andrewd23 :
hipro power supply hp-3017f3
Well, I found one review from 2009 at www.johnnyguru.com for the K series 550W; it did average.
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story5&reid=148
Couple other forums where members said they wouldn't buy them or install them, but if they were in a pre-built already and still working they would probably be o.k. with the video card upgrades in question (0lder 6670 Radeons, use a bit more wattage/amps then the 750TI and run hotter). And quite a few that said to replace it if you are going to be gaming.
So, maybe you might want to save for the video card and splurge on a new PSU that will run it without any stressing out over power, heat, failure. Here's one that will fit into your case, has enough power, is of very good quality, and should leave you some money towards a new video card:
SeaSonic S12II 430B 430W ATX12V V2.3/EPS12V 80 PLUS BRONZE Certified Active PFC Power Supply
5 year warranty.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151074&ignorebbr=1
A little more money, but more power and a longer warranty - 7 years;
EVGA 220-G2-0550-Y1 80 PLUS GOLD 550W ECO Mode Fully Modular NVIDIA SLI Ready and Crossfire Support Continuous Power Supply
Perfect 10/10 Score from JonnyGURU
http://www.newegg.com/Product/Product.aspx?Item=N82E16817438053&ignorebbr=1
Last point, then I am calling it a night; probably won't be back until late Sunday or on Monday - have to work all weekend.
I have been in your shoes, way back around 1999 or 2000; I was just getting into computers, very late in life. Received a great game for my birthday and it wouldn't play on my PC; a real bummer. So I found a serious (for the time) video card and stuck it in the pc and played my heart out. I still don't know how much power that card took, but a cheap ass 180 watt psu in an eMachines ran it for a long time (3-4 years) and for hundreds of hours of gaming before that PSU just didn't turn on one day.
The best solution is to buy both, but I think you would be alright for awhile if you got just the 750Ti for now: as long as it doesn't take any extra power leads. If you can figure a way to come up with a little more money (beg, borrow, open a credit account, work a little extra) and buy the EVGA psu and the video card - that would be the best solution.
Hope this last blurb helps.
Have a good night and a good weekend.