What ancillary services can a computer programmer offer?
The other part of me (the part that works with friends, and is loyal to employees) loves your question!
With 12 years in business, you should start by reaching out to current (and former) clients and asking them the same question. How have their needs changed over time, and are there new opportunities that you can address? As they look to reduce costs are there projects (like ongoing software maintenance) that you can help with?
You may also want to expand your reach. Programming, while once local, is now global -- try some online ads and search engine marketing to see if you can take on projects for clients in other geographic locations.