If you drove it to the shop and the only symptom is the trans fluid leaking out then I think that you have a leak in your transmission cooler or a cooler line. The transmission should be fine. You may have experienced the trans acting up because of the low fluid level. It should be fine once the leak is fixed and the fluid level is proper. If coolant mixed in with trans fluid then both systems will need to be flushed but it is unlikely that is the case. Good luck.