No power steering

[smn159]

The power steering has stopped doing it's thing on my wife's E46 tonight. It was fine when she drove home from work but steering was extremely heavy when she went to go out in it tonight.

Belt looks OK, but the PS fluid is black and smelly, although the level looks OK. Am I looking at a new PS pump? Any recommendations for a good specialist / general garage to change it near Aylesbury, and a ballpark price?

Cheers,
Simon