Going to be changing my brake pads at some point, but took the wheel off today and the bolt i need to undo seems to be a star shape.

I just wondered if anyone could tell me of a way of getting them off or where to get a socket to take them off?

And also i was looking at getting some brake pads, just wondered if anyone knows if these would fit? http://cgi.ebay.co.uk/VAUXHALL-ASTRA...es_CarParts_SM

Or if anyone could recommend anywhere to get some
Ive got a mk4 '99 1.6 16v with ABS.