Ian having a problem completing the setup for the new Apple Photo's Beta, as it tells me I need 29GB additional storage space on my hard drive.

I have a MacBook Air 256Gb with 18GB remaining. iPhoto was working fine for me before this. I have 133Gb of Movies and 44Gb of photos in iPhoto (a lot I know!)

My problem is I can't try and clean up the existing movies/ photos as I can't open iPhoto anymore in order to delete stuff. Help?! What do I do?

I do have a 2TB Time Capsule and I have a copy of "iPhoto Library Manager" - is there a way to temporarily move a bunch of videos onto the time Capsule without losing their metadata, and then move them back later? 

Or has anyone got any other suggestions to help me out? Thanks!