I've got a sugoi rain cover--it has been worth it in both rain and windy conditions. sometimes you can find these on the cheap at an LBS.

I am not sure about arm/leg warmers. My only experience has been w/my arm/leg warmers. I have gained about 25 lbs in the past few years (in law school--not as much exercise and poor eating habits. changing that now). My arm/leg warmers have adjusted w/me w/out a problem.

If your lbs has them, try them on and then order the same brand on-line for cheap.

some info I have learned over the years: certain brands use Euro sizing and are thus smaller (ex: I wear a medium short, but in Castelli--I wear a large)
examples of euro brands/sizing: castelli, exte ondo
examples of american sizing: Terry, Pearl Izumi, bellweather

good luck in your search and keep us posted!