Data input/output

Hello,
I have faced a problem and dont know how to solve it.

The problem is I wanted to make a excel document that recognize symbol and gives me value that is written down somewhere before. Example:
Symbol "A" is 225, "B" 230, I need to write down all the letters, each has different value, also "A" and "a" has different values. So what I want to do is, when I enter words (each letter in different cell) it will give me a value that is defined before. I hope wrote it simple enough.

Next step would be that excel is able to give me a number from two letters, example have written "C A T", it will understand the symbols C and A, and A; T and will give me value that is defined before.

The thing is I am trying to make an excel file that will calculate widths of words, each letter has different width, and different letters have different gap sizes between them.

If anyone has any ideas, please let me know.

Janis