Visa panic (Colombo)

Visa hiccup experiences, anyone?
I wanted 4 months to do some research, they are currently deliberating, but looks like there is a good chance we might only get 3 months. Now I have done enough backpacking in my life to know that there are usually ways around these things... so, what is the way around? Do people do Visa runs? Where? Is there an inconveniently located office you go to and apply for extension?
thanks,
Britta