It really helps to know what kind of begonia you have. I know--most of us thought 'a begonia is a begonia' when we started out! I always recommend the site of the American Begonia Society, and refer to it often myself. Basically, I don't think you can go wrong with a potting mix that drains quickly but holds some moisture--in other words, not clay and not sand! I don't think any begonias like full sun (tho' some are grown there!) but some kinds like more sun than others. The ABS site has a basic explanation of what the types are and what culture they need, plus lots of pictures that may help you find what you have. Then you can come back here and ask moe specific questions. Begonias are a fascinating plant group, with thousands of species and hybrids. Very addicting too! Good growing!

Sweet, Thanks a lot. I'll look into that and see what I can do with mine.