Need A/C Help!!!!!

[iluvmy72]

OK guys....I know this site is for our trucks mainley....however the old hen is nagging me and this board has helped me in the past. The A/C on my old lady's 96 Astro Van biffed it this last week. She said it started by only working on the highway or going fast. Then the thing started to not be cold at all while idling at lights. Then a few days later, she can hear a noise when the A/C was on and sounding like a noisy scraping sound. I drove it to see what was happening and it makes a noise with hot air and it revs high before going into first gear. I didn't know the A/C could effect that but it does. Anyone have any clues? Thanks