the fix was to update my router's firmware. its previous version was from 2005 and the latest version available it from feb 2012.
(before you do this, make sure you take note of all of the router settings. i snapped a quick pic of all of the pages that looked too complicated for me to remember
per linksys's website's instructions I:
reset the router.
power cycled it, w/ 10secs off.
confirmed settings setup back to the way they were (which oddly enough they were already set(?). i thought that holding in the reset button in the back until to the power button flashed would've reset to factory defaults, but it didn't..)
by the time I picked up the gs4 to see what was up, it was already connected.