erm, it might be cheaper to just take images as files to your print room, presuming you've got one. costs mount up when running a printer. Still, I was recommended this model for a large format printer on the cheap http://www.amazon.co.uk/Canon-PIXMA-...=2C45QPCJ2YOW2 . Still, I suggest getting friendly with your uni printer bloke.
btw, you at uni in london?
Have a look at the HP OfficeJet K7100. You should be able to pick one up for under £200.
The biggest issue with producing your own full colour prints at this size is the price of each print rather than the cost of the hardware. I'm sure you can find comparisons between the big manufacturers / models if you search around. I doubt that HP are the cheapest, but I'm very satisfied with the results I get.