Cari – your wedding sounds so pretty! One idea I plan on using in my bouquet is to have an accent color wrapped in ribbon at the base of my bouquet. That way, you can use the subtle cream and whites in your flowers and then have the green accent to tie it all in.
For your reception, I think it would be fun to use mainly your white colors and then have the favor boxes or personalized napkins in your green color! Not sure exactly what shade of green you are searching for, but I found a really cool green 'margarita' color on this site: http://www.myjeanm.com/engine.cfm?iCatID=29597
The best part is you can use any color on any invite. I've been playing around with the different options for hours already! And I think they just announced a new video contest where you can win free wedding stuff and get to be on a TV show! Sweet! http://memelabs.com/jeanm/
Congrats on your wedding Cari and best wishes in your planning!