What to wear?!

Ok, So I have an interview on monday as a school nurse at a private elementary school..

I haven't worked in ages, since i was pregnant and all.. and well.. i have no idea what the heck to wear?!

what do you wear to an interview? cause both of the previous jobs i had, i wore scrubs cause i got hired on the spot cause they were my mom's friends lol..

i definately need to buy something cause i don't have anything nice to wear..

any tips, ideas or whatever?! please share!