Wasnt a transfer to and from the hotel included in her package? I am assumming not.
I say, BE HONEST, otherwise things will get ugly. You cant read each others minds adn this is something that is bothering you. Me personally, I would just give her a gift/hair/makeup and pay for her cab, but thats cause I dont know how to say no and im too nice sometimes, which blows. She still is making the trip down to your wedding, which is huge in itself for someone with money issues.