How/where do i find a power supply that is this small?

Those are custom made for that specific computer, and you cannot buy standard "replacement PSU" for those types. Any replacement would be the same wattage. Even if you could find a higher wattage, your case is also probably small, and would have poor cooling capability for any large upgrades (too much heat inside if running more power).

Bottom line, you cannot really upgrade a machine like that, at least not video upgrades that are meaningful. That all said, I've seen one such small system run a GT610 low profile video card with a 240W PSU. A lot depends on the quality of the PSU itself, whether it can run a GT610 with such a low power rating.

Here you go eBay have some 300W replacements

http://www.ebay.com/itm/NEW-300W-Delta-DPS-220UB-A-Power-Supply-replace-upgrade-/330813536666
HTH
David

If the manufacturer of the computer isn't an option - try newegg.com or tigerdirect.com - but as far as form-factor power supplies, you might be stuck having to get a standard one and transfer your computer over to another case.

By that point you might as well cut your losses and buy a bare-bones machine with a new case, power supply, motherboard, and processor - some toss in some extras like ram, or a basic video card.