Alright everybody I've figured it out with the gearboxes and motors.
For the drivetrain I'm going to use
http://www.andymark.com/Motor-p/am-0912.htm?CartID=8
this motor and
http://www.andymark.com/product-p/am-3105.htm?CartID=7
this gearbox.
For an "arm-like" function I'm going to use
http://www.andymark.com/Motor-p/am-0255.htm?CartID=10
this motor and
http://www.andymark.com/product-p/am-3106.htm?CartID=9
this gearbox.
Thanks for all the help!