OK this is one of two fig trees for first time ever figger.

I bought the tree at a hardware store and it already has 5 or 6 little green figs on it, but its about 5 feet tall and narrow as a blade of grass.

Although it seems to be growing well this is not the shape of tree I want, let alone the fact I'm worried with it outside it may even blow over and break!   

Can I prune off the top say foot or so now, above the figs, or is it recommended to wait to do any pruning until fall after you harvest the fruits?    I would think that would encourage it to fill out width-wise but just wanted to make sure.  

???

Jeff, you have a great opportunity here. If you anchor the tree with a tall bamboo stick, you can set up a nice air layer for the top and end up with two trees. It will encourage branching on the mother portion for next season as well, so you won't have to deal with a "tower" again. I would wait until the tree fruits ( if any figs ripen) before cutting the air layer, but it should work out in your favor!

Welcome. Where do you live? Are you planning on keeping this in a pot or planting it in the ground? Where I live the figs end up growing more like a bush than a tree. I keep most of them in pots about 3 trunks per pot. Either way I would air layer that top and when it roots out, plant it next to the parent tree. That way you will have a bushier planting and hopefully more figs next year.

Central Illinois and so far I plan to keep it in pot outside and winter inside under lights.    Its a Black Mission fig. 

I'm not sure I understand what an 'air layer' is.  The tree came anchored already to a stick, half way up.   The top half the tree is new growth straight up.

The lower half has fruits up to about half way, they're decent size but all green right now.

What would happen if I now, cut the tree about a foot down from the top, and then tried to root the top part.

Wouldn't it redirect more into branching and fruiting then, instead of getting taller?

That top half is actively growing green wood. It is very difficult to root. I would set an airlayer as previously suggested.

But I don't want a second tree, I don't have any place to plant it :/     OK cutting to the chase.... basically I'm just wondering if I lop off the top of the tree will it start growing sideways like any other plant, or will that cause it to drop its figs.

Must of us pinch top bud to promote fruiting and branching, I have trimmed a foot or so of for trees that I tough were to high for my liking and no problem. You can experiment with that branch,

Up pot the plant and use a taller stake. Prune when dormant.