Before seeking T replacement therapy, I would work first on improving my diet, sleep, and excercise routine for a while then get retested. And one low Testosterone test is no indication of low T, you need several tests taken averaged out to give you a more accurate number, T levels vary greatly througout the day.
Next if this doesn't have an appreciable affect, I would ask my doctor about clomid or nolvadex treatment (prefer nolvadex). This is a short term therapy used to boost your T production. Use google to look up the therapy and side effects. If your levels are in the 200's and your doctor doesn't think treatment is necessary, ask to see a specialist. The standard T level varies from 200 to 800, but if your average is always low then you definitely have a problem.
And last of course there is T replacement therapy. There are gels that are self administered and injections that either you or your doctor will administer. If I felt I had to go this route I would choose the injections, they seem to have a better effect and you don't have to worry about getting gel on women or children.