I'd like to know if there is something I can do to close the gap or hide the gap in the blinds. Obviously, I can measure properly and purchase new ones but really trying to avoid that.
I've also thought about curtains, but it's also something I'd like to avoid. Are there any solutions to this?
Here is another photo zoomed out. 
Buy one more set of blinds 3" wide and hang it in between these two. Just ask for "mini blinds" at your local big box store and they'll put you on the right track.