You have to understand that almost all orchids CAN NOT grow in potting soil. Their roots are special in that they require copious amounts of oxygen to survive. Potting soil would smother them and they would quickly die.
Orchids are epiphytes, they grow on another plant or object for support.
The best I can tell you is that I think you have some kind of orchid from the Oncidium Alliance. There is very little hope of exactly identifying which one unless when it flowers it turns out to be a species or a widely grown hybrid that some one recognizes. There are easily 3000species in the Alliance and maybe 12,000 hybrids. Out of flower and in poor health there is no possible way to tell what you have!! The best you can do for now is to follow the general care instructions that I gave you.
If you wanted printed instructions you can go to the American Orchid Society website aos.org and under one of the pull downs you will find culture sheets. They are pdf. Files and you can download and print the one on Oncidium care.
