I work from home too, so I know what you mean. I find that it's very important to get in touch with other people who do a similar job - I have friends who I email regularly and we can exchange ideas about work, which is nearly as good as having office colleagues to talk to. So do see what the network opportunities are (even if you type your job title and town name in a search engine, you may find people living near you with the same job.)

Otherwise, it's very important to have interests that take you out of the house and are social. A good place to start is your local community centre or adult education centre. You can contact them to see what they are offering - events, classes, talks etc are all good ways to make friends. If you have a hobby like walking or dancing you could also use that to meet people by joining a ramblers' group or taking lessons in a new dance style. The internet is also good for friendships, not just dating - if you put 'make new friends in ...' and add your town name you may well find local groups, and there are also national organizations like City Socialisers and Nexus to help people with their social lives.

Good luck!