Memory is really important for AE. It should cost only $80 or so to upgrade to 4GB of RAM and that should help a lot. My rule of thumb is about 2-3s gig of RAM per processor used, + 1 gig leftover for finder/system operations. By that calculation, you are still short a gig for even single process use. Maybe snow leopard uses more memory than leopard, so it spares less for AE.
I don’t know that a solid state drive is much faster than a physical one. I thought the big advantage of those was no moving parts and less power consumption. Personally, if you do a lot of AE work, I’d invest in a desktop. I think AE needs the horsepower and screen size.