Can I plug a USB hub into a Toshiba model CL 15 -C1310 laptop that has only 1 USB port?

Yep, sure can. just note the total power of devices can't exceed 500 Ma unless the hub has external power support.

Yes, you can.  It'll be slow, though.

Where else would you plug it in ??????

hubs are fine if you aren't using the devices at the same time, like keyboard and mouse.
they fail when transferring to/from multiple flash drives or data heavy devices, as you still only have a single USB connection to/from the computer...

Yes, no problem.