i know wot u mean, i have being thru something like this myself and my friend's gf is like some Managing Director's daughter who lives at like Mosman and is already driving her lexus at the age of 19.
the simple answer is, if she is going out with u, obviously she is cool with the person u are. hence money to her is prob not a major issue.
Being a guy, having money certainly helps, though if u guys are totally in love with each other, then i guess u have more to offer than wotz in ur wallet. Mean time if u still feel inadequate, go get a job, or get a head start in ur career. Start soemthing that u think will of be future importance and can add value to urself.