How much to get my AC looked at?

I've mainly been using heat and nothing, but today it was 68 F out and it was quite warmer in my car and I got the AC going full blast and it doesn't seem to be doing much. When it was a bit cooler out and I had the AC on a lower setting I could feel it. Now it just feels like a breeze that's not cold or hot. I remember having such issues last summer where I would still be hot after a 15 minute drive home, from work.

How much do you think it would cost me to have it looked at and how much to fix depending what it is? I remember this glass view in the AC line and it has some fluid in it butt not much. I remember trying to figure this out once and there was maybe no fluid.

I need to take it in for the latest recall still. Thinking I could have them take a look at my AC too.

Edit, 2010 171k miles.

Thanks,
Higgins909