I'd say "go ahead!" I don't know what to tell you about how to find someone but you might ask around...look at bulletin boards,etc.
We have someone come 1x/month and I'm hoping to up it to 2x/month. (Honestly, if 1 week was even remotely possible I'd do that!!)
We have a woman who basically retired and wants to earn money and keep busy/active. We pay her $125 for 1x/month and she quoted us $190 for 2x a month. I do think this is a lot but you know what, it's worth it to me. And, I know that she has to pay for insurance and stuff and private health insurance. It will really depend of who you find, the size of your house, and what you want them to do. If you want help with dishes and stuff you might look for a "mother's helper" if you want scrubbing tubs, etc. look for a "house cleaner"
I still do a ton of work around here...so does my dh. Like a previous poster mentioned, we generally don't ask her to load/unload dishes, laundry, etc. But you know what, she would do anything for me. (you know, cleaning wise!)
I spend that time with my kids doing the normal stuff we do...playing outside, reading stories in the playroom, etc. I try to keep them out though so they don't pull toys out in rooms she hasn't cleaned yet. I feel comfortable enough to leave her here while I take my kids out. Of course, we've built up our relationship...and I found her name by a friend of mine who knew her for a long time so I felt better going into it.