Wanting a third monitor

I purchased this PC in 2014 and it is performing great. I have been wanting to add a third monitor but in my research, I have read that my video card would not support a third monitor. If this is true could someone please verify this, and if possible recommend a card that would run on my existing system. I have to add that I do not use this PC for gaming except for Farming Simulator, I use this with an architectural drawing program. I believe this is mostly the complete list of information.  AMD RADEON R7 250 2GB GDDR3 PCI-E 3.0
 THERMALTAKE SMART SERIES SP-750PCBUS 750W 80PLUS
MSI 970G43 MAINBOARD
AZZA FUSION 3000 FULL TOWER
COOLERMASTER SEIDON 120M WATER COOLER
2 -  4GB CORSAIR VENGEANCE 1866MHZ DDR3
1TB SATA III 7200 RPM 3.5" HARD DRIVE
AMD FX™-8320 EIGHT-CORE PROCESSOR
64-BIT OPERATING SYSTEM
WINDOWS 10
Added 1tb ssd

https://www.amazon.com/gp/product/B007L6NYAO/ref=oh_aui_detailpage_o08_s01?ie=UTF8&psc=1

that motherboard is sporting two slots for pci x16 video cards.  the r7 250 may or may not support three monitors, it depends on the model. if it has a display port output , it probably will run 3 displays with the right adapter. a display port looks like an hdmi, except it only has one beveled corner.  whereas the hdmi has two, but the second pci x16 slot will prolly take an additional r7 250 and you may get the second card to output multiple monitors as well. it doesn't even have to be an identical card or bridged with a crossfire config, it could be an r5 220 or something, as long as your driver is compatible.