Here's my point of view: IF and only IF it is "only" a yeast infection use yoghurt and apply it just like you would a regular yeast infection medication - be a little creative... ;-) I don't want to be too graphic since we do have a male audience here as well.. I've managed a number of yeast infections that way in the past as I am highly allergic to the regular medication. Usually the good bacteria will kill the yeast and after a few days you'll feel fine.
If the doctor isn't 100% sure about what you have I'd be VERY careful about taking Antibiotics . Just my 2 cents... Especially two at the same time sounds really weird. I looked them up and they seem to treat the same thing (urinary and vaginal infections). To me it sounds like overkill.
If you do choose to use Antibiotics you need to break the fast BEFORE starting to take them. Otherwise your stomach might very well go beserk and you'll feel ill.