In the mean time there are several things you can do. Firstly, if your girl is quite irritated, you could try a little benadryl for her. The typical dose used in dogs for this is around 1mg per pound of body weight up to twice daily. You could also purchase some ear cleaning solution from you local pet store. There are several different brands here including epi-otic and oto-cleanse. You need to follow the instructions here and be sure to give the entire ear canal a good massage after applying the solution (from the outside). Please see: http://hubpages.com/hub/Pet_Tips_for_Dog_Owners_-_How_to_Clean_Your_Dogs_Ears for more information on how to do this properly.
You should also treat your girl using a good ear mite product such as Advocate (this also kills fleas, flea larvae and even some intestinal worms). These three things will definitely put you in good stead for your Vet visit and hopefully give you girl some temporary relief until an exact diagnosis can be made and some ear ointment prescribed.
Best of luck with Nala and let me know how you get on.