budm, according to my newbie knowledge, these UPS are designed such that it reuses the big input transformer for output too via cleverly designed relay network.
This is the datasheet of the cap:
http://www.epcos.com/inf/20/20/db/fc...MKT_B32232.pdf
Unfortunately, I can't buy it a piece from the manufacturer and everyone else is charging $15+ for something inferior, and my bet seems to be to buy it from an online catalog store OR get those fan starter caps like these:
http://i.stack.imgur.com/FZBrg.jpg
I have no idea what the specs for those fan starter caps could be.