I'm sorry that I have a bad news. You bought the old (I mean not the new) model. I'm from Czech Republic and I bought the new 2TB model (2011). The price was about 265 €, so the same as the 1TB old model. The model number for the 4th generation 2TB is MD032LL/A. So I expect that it must be the same in Spain as it is in Czech Republic.
So if you have a chance give the time capsule back to the shop and buy the new 2TB version. I've checked the Spanish Apple website and you can buy the 2TB model for 279 €.