• My MB Pro only has two USB ports and two of my peripherals MUST be plugged directly into those to operate.
Sorry, I have never heard of this. Could you please elaborate?
The best (only?) solution to your problem - needing more USB ports - is to install a powered USB hub. The hub must be self powered, i.e. plugs into the wall. It is an external device, not an add-on card. However the hub itself has to be connected to your MBP, so there goes one of those ports for that purpose.
Hubs come with a varying number of ports, 4, 6, 8, etc. and cost about $20.00.