Nothing you do to your current vehicle will increase the carrying capacity by one pound. The axle capacity along with the tires max load have set the payload capacity of that vehicle. A glance at the Trailer Life towing guide for 2013 shows that SUV has a max towing capacity of 7900 pounds:
LinkLook at the sticker on the driver's side door post for the actual numbers for that SUV.
You need a newer one ton pickup with dual rear wheels to even think about hauling a 45 ft TT. I say newer since the trucks starting around 2011 have seen a major increase in towing and payload capacities.
