If your maid is locally hired/own their own sponsorship, usually paid between QR1200 up to QR2000. But the one you hire from agency, usually paid only between QR700-900/month (since the cost of the agent is very expensive : Qr7000 up to 9000 !!!

But most of westerners over a very good salary up to QR3000.

It's depend on your generousity and the work/behaviour of your future maid. If she works good, I believe she deserve good salary too.