I bought fm12 when it first came out, for what was it £24?, even if not much has changed since fm11, fm12 is bit more polished and improved, hell even if it only would have keept me entertained for a couple of months that would have been a good investment, and seeing that im still playing fm12 and cant see myself go back to fm11 id say its well worth it
I think fm 12 is better than 11 and is worth buying. Not drastically better or different but slightly better. Since you're buying a brand new laptop I'm assuming purchasing one piece of software is within your budget.
I'd wait for FM13 at this point, honestly. I just bought FM12 and find myself still playing my FM11 saves... FM12 looks a great game so far, though, but there isn't too much difference. I might recommend getting FM12 just so you are familiar with the changes they will transfer over to FM13.