I had similar problems too.. I left school at end of year 10 and all my friends stayed on and did other things and none of them have kids so we barely talk. Work was no good as everyone was heaps older than me and then we moved to the country so we hardly knew anyone and had to start all over again. We still keep in contact with a couple of hubbies mates and their girlfriends but its not really the same. I managed to make a couple of friends by selling avon as i got an excuse to go around and meet my neighbours. I also started going to a playgroup and a little learners group for the kids, got the details of these from my child health nurse and after a while of going along to these things people eventually become more friendly and i'm now starting to really enjoy going.
You could also maybe try to get a part time job if your partner would support that as that could help you to interact with others. If that's not to your liking you could go and join a sporting club like tennis, womens soccer or something. I've done the soccer before and that was great and keeps you fit. Otherwise you could check out the local papers and go along to day classes for maybe craft days or something like that, one's aimed for kids or adults really.
Lastly all i can think of is maybe to go and volunteer somewhere, if you can't get someone to watch bubs then see if you can find something where you can take them along... maybe you could visit the elderly in nursing homes with bubs and talk to them... it would make there day and you'd have an adult to talk to. May not sound too glamerous but they are still people and you can have friends of all ages if you have an open mind.
Failing all that or just if you like you can talk to me on my email, i'm always looking to have a chat.
Its [email protected]
Hope some of that has helped.
Oh - another one i've thought of is to go to your local library and see what groups or activities they have on offer as they are usually free or cheap and a good meeting point.