Cat Pics
Get a humane trap, like the SPCA style. The ones at Tractor Supply are OK, but the door can smack the cat in the *** which can't be comfortable, especially since the cat is in the process of being trapped and confined.
...and the TNR that poor girl so she will stop having litters.
You could also make a drop trap. I made a real nice one out of closet maid shelving, 1x4 stock, electrical box covers, rabbit wire, and zip ties. It's about 4 foot square and has trapped six cats at a time once.
I even added a door made out of a small BBQ grill grate and U channel shelving standards.