Judging from your choice of video card, you are not much into games. So, you will only be using a Dual core or at most a tri-core CPU so power consumption is not really a big concern.
As for a PSU, I'd recommend that you get at least a 500W one so that you will still have some room for upgrades. Don't worry about the unused power as your pc will only use up what it needs. A good 80plus certified PSU is highly recommended.
With the UPS, 300Watts should be fine, but it can only let your PC run for around 3-7 minutes. I would recommend at least a 650VA or 1000VA. APC units are very reliable, but quite expensive. If you are on a tight budget, I would highly recommend FSP or FSP Group units instead. The company is very well known for producing high quality power supplies like the FSP Aurum (80Plus Gold certified).
And again ; i'm so happy not to have an I.Q. of 140 or more and therefore not allowed to answer. When i click on your link i get this : The requested page was not found on this server. Probably just me beiing stupid. Huhuh, yeah, cool, yeah, huhuh. I'm going to take a walk on my knuckels now, bye.
I have never taken an IQ test before. I would guess it will probably be around 56. However a few shots of 18 year old Macallan Scotch should bring it up to around 75. Therefore, I will not provide an answer to your question.
LOL ! Or try a windmill, i'm from Holland and we've got a lot of them here ! Sorry leogaz but with arrogant statements like "only people with an I.Q. of 140 . . .etc." you can expect reactions like this, you little Brainiac ! ( especially from dumb nuckelheads like me )