check out the place in the alkhor industrial area looking towards alkhor. ask around when there they will show you.

if you have google earth or have a GPS here are the coordinates.

25°42'28.86"N
51°30'12.21"E

1 week 1200Qr
3 week 1800Qr
etc.

but you could get a oneoff course from some guy there and just try the exam if you already have a license from some other country. that will be about 200Qr unofficially.

I'd go for the 1 week if my skills are right.