Looking for some input - Upgrades

[elite]

I have a HPE 141F computer (the specs can be found by following the link):

http://h10025.www1.hp.com/ewfrf/wc/d...roduct=4120525

I have a few concerns I would like to address.

I have run out of sata ports on my motherboard. I currently have connected 2 1tb's, a 500gb, and a dvd burner. I also have 2 more (1 1tb and 1 1.5tb) hard drives in external enclosures. At first I was fine with it but recently I have been checking the enclosures and it seems they are running quite hot. I also was wanting to pick up another 2tb western digital but I do not want to put it into an enclosure. I would like to get away from them. I was looking at a controller card and this seems like it would be the best solution for this problem:

http://www.memoryexpress.com/Products/MX13053

Would this be the best way to go? It sucks that two of the sata ports are on the outside but I could probably get a longer sata cable to compensate for it. Or would something like this be better:

http://www.memoryexpress.com/Products/MX23479

I could just pick up an e-sata card and go about it that way.

Secondly what kind of wattage for a psu would I need. The pc currently only has a 300 watt psu and I would be swapping out video cards as well to the evga gt440. I am guessing around 600 watts would be more than enough?

Lastly if I were to go the controller card route would it be possible to get one that supports sata 3 and use sata 3 even though the ports on my motherboard are only sata 2? Or would I be only able to use sata 2?

[GTi-RS]

If you are looking to just increase storage then consolidating your drives into a bigger one/two may be more cost-effective.

SATA2 on-board will work with SATA2 not SATA3. ( no real advantage to go SATA3 for you anyways)

600W PS is plenty, but get a good one (80+ certified from a good brand).