Flash Programming is my favorite among other software because I can create animation and others. I admit that I still have time to learn more in this kind of software so that I can apply this in the near future.
Your OS is still okay, but for the fastest speed add more RAM and you will perform your work with no hassle. My computer also was upgraded and now we've been using it for 2 years till now.
It is very expensive if you will try to replace a new screen. As you said the color of it run all over the place. For replacing the screen you will pay for the screen itself, labor etc.and will cost somehow $250 - $400. I suggest you buy a new laptop instead of replacing a screen only.