... ahem, Cornellà stadium is not in Barcelona but in Cornellà de Llobregat... a different city altogether --yeah, bordering Barcelona, but it's a separate city. So you know.
Sadly I don't recommend hotels... I do live here in Barcelona and have no use for them :)) In any case, do you really need to stay in Cornellà?... it's rather a semi-dormitory town with little interest (apologies to any cornellenc reading this post!). The stadium, which I would imagine is RCD Espanyol, right?, is reachable from the centre of Barcelona in 45' or so by train or metro (depending where you stay in Barcelona). Just reflectin'