How do you make a weak relationship into a strong one?

So, my and my girlfriend had some problems in the past, we split up, she met a new guy, and that was that. After a few weeks of this new guy she realized that she still loved me, and she wanted me back. Well since I love her dearly I took her back right away. Now our relationship is pretty weak and to make matters worse, we have to go into a long-distance relationship for about 3 months now. I am a very physically attached person, and have never been into a relationship that was only emotionally attached for a long period of time, and to make matters worse, I have a tendency to be jealous, and get worried alot.

My question is this:
How can I make this weak re-starting of a relationship, into the strong one we had in the past, when we have to be very distant from eachother for about 3 months? We love eachother, but the feelings just aren't the same because our future doesn't look too bright right now...and I want this to work so bad, but I feel like I won't be able to take not seeing her and worrying about things.

Any advice for me on how to make this work? We will talk over the internet, through AOL instant messenger, and email, but that's about it..for 3 months - btw we have a 6 yr. past best friendship and a 16 month past relationship that went pretty sour after awhile behind us.

Thank You to any of you that give advice.
Take Care,
X.