Drjay, the original switch is round, which should make installing a replacement easier, although you may need to do some minor modification to get the new switch to fit. Digi-Key has a selection of 16A 120V round pushbutton switches, and one 20A 120V round pushbutton switch in stock. You may also be able to use a toggle switch in place of a pushbutton, if it should come down to that.
http://www.digikey.com/product-detail/en/C7000AFBB/1091-1038-ND/2747869
http://www.digikey.com/product-detail/en/PR141C1100/EG4696-ND/2116175
http://www.digikey.com/product-detail/en/PA301/432-1205-ND/696600
.
http://www.digikey.com/product-detail/en/C7000AFBB/1091-1038-ND/2747869
http://www.digikey.com/product-detail/en/PR141C1100/EG4696-ND/2116175
http://www.digikey.com/product-detail/en/PA301/432-1205-ND/696600
.