Where to go …..

I am currently in a reporter (DBO) position. I mainly use MS Access. I am trying to get a game plan together so I can strive for MCDBA. I use SQL loosely. I use it but only the basics I haven’t really used SQL in several years. I got lazy and used the wizard on the application. I am trying to shake the rust off and dive head in. I am trying to find out what would be the cheapest approach to getting started. I started looking and I found that I have to take windows admin test as well. I know how to use windows but never gone in dept with any of the versions. What approach/angle should I approach …any ideas