Please, please help me.

You can still send your girlfriend gifts. First, you can always mail them to her. Second, a very good way to make her feel loved is to send her very heart-felt cards that you've made yourself, either email cards or paper and envelope in the mail.

Also, make sure she knows the entire situation about that other girl who won't leave you alone so she knows she can trust you instead of the lying girl.

Have you got a digital camera? Take some sweet, crazy pics for her like of you holding up a sign out of a window that says, "I love you!" Or go to all the places in your town you've been together, take a pic of yourself there and write a msg under pic telling her what your favorite memory of her you have from this location. A pics worth a thousand words!

I know it's not much but I hope it helps: just simply arrange a day with her where you can both go to the place you first met and do something there. I'm sure it will make her happy. Ps don't take my word completely because I can't say I have had loads if experience with girlfriends but try it.