how to extract column letter of a cell & select cell by referencing its column number

If I have a named cell in the worksheet, "myCell", how can I extract it's column letter using VB?

Also, in addition to the above, if I have a column number (not letter) and a row number of a cell, how can I use that info to select that cell in my worksheet? So for example, I want to be able to select cell C5, (and all my sub knows is the cell's row, which is 5, and column number which is 3).

Thank you.