If you are a qualified proof reader then you're certainly not deluding yourself because with all of today's technology, this is something you can easily do from home. Indeed, I have a friend who used to do this and she was told by the companies who used her that good proof readers were so hard to find.
As usual, andy hughes has come up with probably the best suggestion in your local library being your first point of call, but you could also try contacting printing companies directly - or in fact anybody that issues publications; they all have to be proof read. www.yell.com is the Yellow Pages online site, so you can amass as many company contacts as you wish from there.
If you're successful in proof reading, then moving onto editing shouldn't be too much of a problem in the future.
Good luck.