For the OP, you say you're goal is to get a girlfriend. I think that is a little misguided and your goals might change if you spend some time reading posts on here, but the best way to find a girlfriend, in my opinion, is to meet girls through your social circle. I know almost every girl I have ever been in a relationship with or exclusively dated, I have met through friends or through my social circle. It's just a lot easier to get to know someone if you can hang out with them first. Not to say you should be friends with a girl before you enter into a relationship with her, but it's beneficial to be acquainted first. It cuts out the middle man so to speak, and dates are a lot more productive in getting to know each other. There are no "games" or potential for flakey behavior. In some cases, dates might not even be necessary. I've had relationships come out of hook-ups before, where a I've gotten to know the girl through hanging out with her and her friends (my friends too), one thing led to another at a party or something and I ended up going home with her. It's pretty easy to develop a rapport with a girl when you are laying next to her in bed.
The girl I am currently dating (I guess you could say it's exclusive), we have known each other since a class we had together in college when I was a senior and she was a junior. We worked on group projects together and stuff and went out to parties a few times. So, when we met up earlier this year and went out on some dates, her IL was already high as hell and it didn't take long for us to catch on as boyfriend-girlfriend.
That said, I think it is best for you to develop a good social circle and not necessarily by calling up your old high school buddies. If you don't like them, then don't hang out with them. There is nothing worse than hanging out with people you don't like. You should try to make some new friends. Are there dudes your age who you work with? See what they are doing after work on a Friday and ask them if they're interested in going out and getting a drink or something. I think you should also join a gym and get into shape. I post this all the time on here, but a gym is a good place to make friends with other dudes because you're constantly running into the same guys there.
Though, I don't think you should make finding a girlfriend as your goal. In my experience, when you intentionally set out looking for a quality girlfriend, that's the last thing you end up finding. With your current mindset of having to be in an LTR in six months, you're setting yourself up for a bad situation. I have a good feeling you'll end up settling for a BPD and you'll be way worse off than you are now. You should instead make your six month goal something like bettering yourself and dating a couple different women. You've never had sex before, and that is something you could shoot for as well.
Truthfully, it sounds like you're biggest problem is just that you're shy and not very assertive. If a guy who is above average in looks and well-dressed puts himself out there in a confident manner, he is bound to get a response from plenty of girls.