Friends are probably one of the worst groups to look for fans. You want to find people who like comics, and who enjoy the specific comic that you happen to be writing - and being your friend or relation doesn't mean they're going to fall into that group. Most of the people I know do not read comics, full stop.
Look at it like this - say you've got 100,000 readers who all think your comic is the best thing. Sounds like a lot of people - but they'll most likely be spread across the world, which has a population of maybe 7 billion. So what are the chances of you running into any of them by accident?
My advice is do what you're doing now: post on forums, actively talk to people, tell people who like webcomics that you have a webcomic - because these are the guys who will actually read it, and will give you useful critique. And yeah, put your banner in your sig somehow. Good luck!