Oil Pump replacement cost

Hi guys. Sorry to burden your forums with question of "How much?" and "HOW MUCH!" But I've recently come into some repair problems.

I own a late EF Ford Fairmont which has recently hit a problem in low oil pressure.
The oil's fine and full.
The engine is making some noises.

From reading around the internet, I've found one of the problems could be the oil pump. I've contacted a few repairers and no one will give me a price over the phone, but I work 8-6pm, so I can't get the car to them!

Can anyone give me the roughest of estimates, at what I'm looking at here?
(I mean, it's Xmas soon too, so I've now got some budgetting to do!)

Cheers.