Maybe you could buy some seeds online of this very pretty plant, so many different companies sell them, if you 'google' the word Gypsophila most of the top companies will come up. Good luck.

Kimberly isn't that small of a town, so I would expect many of the hardware stores and some grocery stores will have the seed among their regular offerings on a seed rack, as well, not to mention nurseries and garden centers.

Try this company, Mizanne. This is there South African site so you will avoid any import problems with the seeds.
http://sakata.co.za/search.php?catname=flowers&species=Gypsophila&Submit=Search