My only problem is I cannot able to make a key's coloumn low and row high at the same time. Help me with the driving mode for the coloumn and row of the keys
I would suggest not to use external resistors (if that is possible), otherwise you have a voltage divider between the internal pullup resistor and the external. This will result in a voltage that is neither High nor Low.
PS: I've posted some time ago a solution for a 3x4 matrix keyboard for PSoC3 and PSoC5. Just for your understanding have a look at it (with PSoC Creator 2.0) Search for "matrix" here or in the PSoCDeveloper forum.