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.