Water softner help?

Hi I have a question about iron removal. So my water hardness is 61 ppm. My iron is 3.5 ppm. I believe its a factor of 8 x 3.5 = 89 hardness. I have a culligan gold 10 series softener from 2007. I had them run my water again because I have rust stains in the bottom of my tub. New tub less than a month old. The hardness was good. But I still have .5 ppm iron passing through my softener.
They recommended I buy a new softener. So instead of dropping a couple thousand. I was looking for some suggestions. Can I buy a changeable wound filter to take it out. I have a whirlpool whole house filter after the softner that regents itself every 7 days. It has a carbon bed in it. I also have a poe sedemet filter before the softener. Can I buy a cheaper air induced filter.
I'm only going to live here for maybe 5 more years. Its only 2 people so I don't want to drop a ton of money on a new softener that isn't even that old. Any help would be much appreciated
thank you, Trevor