Is this power supply any good?

It cost $16 and you want to know if it's good ? :heink:
It's a piece of crap, 480 watts, a single 18 amp 12v rail, litle red voltage switch :lol: :lol: :lol:
It doesn't fit your machine :non:

Yes, you should buy another one, it's going to cost you more to get a decent psu and since you need a slimline you'll need to measure what you've got and do some research before buying another one

Here's an example of a good power supply
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151090
 

No, sorry
It usually helps if we know your video card.
At $40 this 380 watt Antec with a combined 12v output of 28 amps is much more powerful than the pos you had linked, the fact that it has a pcie power connector means it can handle more powerful cards without the use of an adapter, and is as cheap as I'm willing to reccomend
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371033