I took my CCNA on August/2007 so now it's time to recertify

The problem is, I didn't touch any Cisco gear since three years, because I work with Servers & Storage most of the time, and I kind of lost the practical experience.
Since I'm interested more in the design side of things, I'm wondering if it's a good idea to take the CCDA exam ?
My CCNA will expire on 26/August/2010 , so I have less than two months..not sure if it's enough to prepare anyway...
If I take the CCDA exam, my CCNA will be renewed as well right ?
one more question, how much practical experience needed for CCDA ? I have a very good conceptual knowledge, but I don't have a Cisco gear to practice...