How should i go about this friend problem?

Well .. Me jo and laura have always been best friends since nursery(kindergarten) and we have been inseparable until a girl called melina came along in yr 5 we became friends with her but then realised she was bitchy but everyone at our school never had the courage to say we dont like you so as every one was pretending to be nice to her she became popular. In year 6 we were kind of friends with her but not that good, however she got attached to jo and they became good friends so did i as she was going to the same secondary school as her. As we all secretly hated her every one (except for me because she was going to the same school as me) lost touch and started hating on her, i would always meet up with jo, katie, and the boys in year 7 after school. Jo and laura got into an argument with melina and they hated her, so did i secretly but never told anyone except for laura and jo. We all became best friends again and no one got in the way. Melina got popular in secondary school and eventually at the end of year 7 jo, laura and melina made up but said they wouldnt become best friends with her, laura kept the promise but jo didnt. At the start of year 8 melina started her obsession with jo again, jo started to get really close with her but would say they werent best friends. Now it is the middle of year 8 and jo and her are married on facebook, always meeting up and saying they are best friends. Me and laura are best friends still although jo is drifting and i want jo to come back in our group and away from melina although melina is a manipulative ***** who has a different best friend every month however she loves jo so i dont think she will go off of her. Also melina knows im jealous of them being best friends so she likes to rub it in my face by bringing up randomly in conversations that she and jo had the funnest time last weekend or something can u help me on what to do? I am stuck i want jo back :( what do i do?