Need help: I'm a filmmaker/editor and I want to upgrade my current system but can't afford any new fancy $5000 mac.

2013 Late iMac 21.5 fusion drive, running Final Cut Pro X. I'm working off an external SSD (2TB) and the rendering has been great! I just need something to do and wouldn't mind a dope setup for this stuff. Any suggestions? My buget is $1,500-$2,300

Thank you!