Or should I just try to submit a claim with just the password, email address and IP used?
Your claim will need more than just that. Did you ever deposit/withdraw from MtGox using something other than Bitcoin? If so, include that in the claim.
As for your balance, you'll need to figure out what your deposits and withdrawals were, as well as any trades you've done. You need to be within a few bitcoins if you have more than 15 BTC (I believe) in your account.
Otherwise, just talk with MagicalTux in IRC.