Your local center for independent living should have lists of care givers,
see

(usa) www.virtualcil.net/cils/
(Canada) www.cailc.ca/CAILC/text/home_e.html

for one near you.

If you go to a church, that's a good place to ask if anyone there uses caregivers and has names to recommend. Senior Centers often have care giver reference lists ( and will often help you if you are disabled even if you are not 65 yet)

I found the best help by advertising at local university odd job boards (the ads are free if you are disabled and the college uses monster.com for their job boards, which most do). Students who were single parents were generally much more efficient at this work than the young students without kids.

Paying at the higher end of the range for this type of work tended to be more cost effective overall because you tended to get people who got more done per hour at the higher pay range. (this assumes you pay directly)

Employees that don't have to travel far to get to you are more likely to stay.