As you are in a relationship, this is very tough to get out of it. But you should keep it in mind that this kind of relationship is not permitted by Islam. So, you have to try to validate it as early as possible.
In the mean time, tell her not to contact with you more. When you contact even over phone, you should keep it in mind that you are doing a haram work. You should save yourselves from this.
Brother, see, you both can enjoy as you want, but please, be patient until you get married. I understand that it is so tough after having in such relationship, but for the sake of Allah, pass your time to build up yourself instead.
You know, if Allah Subhanahu wa ta'ala wants, he could make your path easy to get married. On the other hand, if he does not, then your path would be very hard and tough. So, just control your emotion for this very short time. Make dua to Allah to be granted and repent to him for the past life. It is a continuous haram work you know!
So, in a word, my earnest request is both of you be patient until you get married and in the mean time beg Allah for a good relationship which would be granted to Allah as well as beg pardon for the past wrong doings.
May Allah grant all of us and our efforts.
Is it wrong in Islam to meet a boy or girl before marriage and holding
hands and talking to each-other at phone?
Yes, it is.