I have found some cool models online, but they're iwo files and doesn't work in DAZ 3, so how do I change them to obj files, DAZ and Wings are my only 3D programs.

inport the ".obj" from an outside folder

The LightWave modelling program is the one that you need to open .lwo files

then you export them out as obj files

import obj files to ds

they will not bend or move in anyway..ie pose and you may need to hand apply any textures , if they have even been uvmapped or materials added..

or you could save a bundle of cash and use PoseRay

https://sites.google.com/site/poseray/home-1 which is free to do the conversion. 

I think Blender can do it as well

I use Right Hemisphere's Deep Exploration.