The fact that you managed to get invited to a party is a good thing. Rule # 1; I would say to set a limit on your alcohol intake, if you do drink. While it helps you come out of your shell a little, too much can cause you to get blacklisted by making an azz of yourself or leave you in a vulnerable situation
When I'm in a group setting, there's bound to be SOMEbody there that has an interest in common. I won't always know which ones they are right away, most of the time the host will introduce me. I try to keep the monologuing under control. Obviously the eye contact is hard for me, I'll try to focus on their shoulder or something. When I talk to familiar people, I've found that 3 sentences/3 lines is good, once I'm able to answer the 'how are you doing?' part.
Your irrelevant past interests might contain enough useful facts to be an asset, especially if any of them are cars or reality shows. If nobody else there knows computers you might instantly become the most popular guy in the room if you walk them through their IT issues
IMO nobody there but your friend has to know your condition unless you feel at ease disclosing that, it's really nobody's business unless someone's safety becomes an issue.
If you do talk to a woman don't give her your contact info before she gives you hers. With that in mind try not to base whether it was a good night or a bad one by the quantity of people you meet. Afterward be sure to let your friend know what you enjoyed about the party and ask what their plans are for the next one
HTH and glad you're here