Caitlin,
Please add your platform and archicad version to your profile signature.
As it happens I know you are on mac and also that there is not yet a sketchup translator for mac for AC11. However, if you do a search you will find several alternatives including exporting your sketchup model in .3ds format and then bringing that into archicad.
IFC is another translator that would work.
Have fun!
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"