[dutchmensport]

As a simple, temporary fix, why no attach a Command Hook on each side of the window (near the bottom). Then take a string, or a thin wire and stretch it across the window and tie each end to the Command hook. Now, when you lower the existing blind, simply tuck it behind the wire / string to hold it against the wall and not dangling down over your head.

Mean while, you can look for another alternative. They do make tracks that can be fit for each side. My Montana High Country has a front living room and a full window in the front. It came factory, with a roller shade and shade simply rests against the valance (turned vertical) on each side of the window.

But for a quick fix, the string and Command Hooks would work and easily removed if they don't, or you swap the blinds out for something different.