You could have done more damage than that. Best to get it into a Sony authorized repair center and have them look at it. I know plenty of people who say they can't afford an extended warranty or insurance on their equipment. It's times like this when you're glad if you have it. Hope you do. :)
well, if it's magenta, you've knocked out your green channel, although it may or may not be the green chip that got damaged. Like Cheno said, I'm afraid it's going to require a trip to a Sony repair facility. It's probably not going to be cheap, but probably cheaper than buying a new DSR-250.