Why you visiting oxford then?
I've never had to get a hotel in oxford, so i cant vouch for any of them, but the head of the river has rooms and is close to the town (the one i mentioned had all the hot german girls in the pub), but then there are loads more dotted around.
below is a few of the really plush ones, depends if u want to stay in a shit hole full of tourists oe splash out on the tits!! just dont stay at the randolph, its far to stuffy rich, fuck face of a place.
Malmaison
www.malmaison.com
The Old Bank Hotel
www.oldbank-hotel.co.uk
Mercure Eastgate Hotel Oxford
www.accorhotels.com
Old Parsonage Hotel
www.oldparsonage-hotel.co.uk
Victoria House
www.victoriahouse-hotel.co.uk
Bath Place Hotel