Potbound, what to do when repotting?

[nogreenthumbs]

I live in an apt, 5th floor, no balcony, so the only time it will see the outside is when we have the windows open. OK, I actually have what's called a Juliet balcony on the East and another on the North. I think the North side would be a good option, but I've got to figure out or get a way to keep them standing up. Also, the wind can be pretty stiff up here compared to ground level. Otherwise it's going to be a windowsill/table plant. Yeah, I should have researched it before I purchased a monster. I figure if it gets WAY too big, I'll donate it to someone local or see if someone local wants to trade for something smaller.