Well, gee, I'm not sure what to tell you.
If your black and white picture is obviously red, there are two real possibilities going on. One is that your red tube is defective, and is overpowering the blue and green tubes. If that's the case, that's pretty much the end of this TV. You certainly wouldn't want to spend the money to have a tube installed, and besides, they aren't available and your original would have to be rebuilt.
The second possibility is that your picture is really magenta, not red, and that would mean that the green tube has a problem. Ironically, the tube is probably OK (unlike a defective red tube that's too intense), and that can be caused by a defective CRT drive card. The tube could also be bad, it's just not as likley.
I think the best bet for you is to consider having a tech come and give you an estimate, but if the cost of repair is going to be any more than $450, buy a new TV instead. In fact, you may want to skip paying the cost of an estimate and just get a new set.
Sorry I don't have more for you to go on, let me know if there's anything else I can do for you, and thanks for using JustAnswer!