Problem with sciatica, cortizone injection did nothing, what kind of doctor should I see?

I seem to be in more and more pain daily. I have been taking norco 10/325 but it barely helps. the pain is completely debilitating. I can't work or do day-to-day activities. It's a SHARP pain on the left side of my lower back radiating down my hip and leg (pain is there all the time!). My effected leg seems to be getting weaker and weaker by the day. I have started to develop a limp when I walk. The pain is accompanied by tingling all the way down to my foot (sometimes). Seems to be getting worse and worse. Since the injection didn't help I was wondering if I had any other treatment options and what kind of specialist I should see. I do not have the financial benefit of going to many different doctors so I want to get it right the first time. Please help.. Can't take the pain much longer and there doesn't seem to be anything that helps as far as I can see.