i don't know what would I do.. in the first place i wouldn't sign the contract, and THEN discover something... I would probably try to discover prior to signing anything....
99% of companies wouldn't review your salary significantly after 1 year, only routine salary raise of 4-5%..don't rely on it..
to negotiate NOW, after signing the contract, even more silly... i wouldn't hire the person which doesn't know what does he/she want... but again, if you are valuable employee and Company feels that they cannot exist without you, your salary might be doubled or even tripled.. but it most unlikely..I doubt it, coz if you could sign the contract without getting into details, most likely you are irresponsible and unattentive...
btw, mind to share your salary? maybe it's not too bad...
on the other hand, if your "life style" is so high, how could you sign something without checking first?
really don't know what i would do...