Open Cart New Custom Field & Tax Field Change

I would like a couple of things to be add and changed in my open cart version. At the moment I would like couple of things changed in open cart product / data area. At the moment open cart has the tax class section and when tax class is selected it add to the price / retail price which is wrong. The tax class should be added only to the wholesale field. Open Cart does not have a wholesale field in the product /data area so need that to be add so the tax class can run off that and not the price/retail. Pretty Simple Change If Know What Your Doing. Should Be Only 1 Or 2 Days Work. Please note freelance will take a commission off the amount that you quote for project once approved.