Are there any areas you're interested in that anda know other people are interested in? Sometimes if anda ask someone about themselves and their inmterests they'll start talking to anda and they'll ask anda about yourself.
I know how hard it can be to talk to new people, but anda can start with a simple "hi, how are you?" and go from there. Even if it takes a couple tries, it will slowly build your confidence and you'll get to a stage where anda can talk to people.
Just go up to people that anda think anda might have things in common with and ask them about themselves and then see where it goes from there.
I hope this helpful, and I know it can be hard but anda will get there.
Don't forget how lucky anda are to have the friend you've got. Maybe, if anda approach a person with your friend beside you, it might boost your confidence a bit as well.
And like Shepard14 said, those who are meant to be your friends will come to you.
This may sound ironic, but just be yourself....People who were MEANT to be your friends will come to you! Even if for a while anda only have one friend, they are the best kind of friend because they like anda for who anda are!