I have a wireless keyboard and it has two key's mapping swapped.  How do I correct the mapping?

1.

Shift (2) = double quotes (") it should be the 'at sign' (@)

Shift single quotes (') = 'at sign' (@) it should be double quotes (")

2.

Back slash (above enter key) prints pound sign. I have no back slash character.

Shift Back slash prints (~).  should be verticle line

Shift (`) [next to One key] prints (¬). Should be (~) [see above]

Shift 3 prints (£). should be (#)