That is not the wattage you listed but the amps on your 12v rail. Need to list the power supply brand and model # or at least the PC brand and model #, also you need to ensure your case has the room to install the card.
Depends on the PSU brand. If it's a good one, you may be able to, that board looks like it uses just under 60 watts of power. I'd get a Radeon 5570 instead, it's faster, and uses less power. Which is a win-win in my book.
If it's an Acer, it's probably not "good". PC vendors tend to change their suppliers depending on who has the lowest price at the time, so hard to say exactly which PSU brand you have. I would not risk running that video card with the GT440. A 5570 should be OK though, it uses 20 watts less power, and is faster. Although even a 5570 is not 100% guranteed to work. If you want to try it, go for it, but keep in mind that there is a chance it won't work, and a very small chance it may damage some other components. I'd say you 80-90% safe with it.
Would be safer to upgrade the power supply then get a new video card.