You'll need to remove the cassette to insert a new spoke... don't bother with a temporary fix... you'll need to accurately measure one of the other drive side spokes to know what length to get.
do it right, and do it once.
if you don't have the tools (guessing you don't, or you wouldn't be asking here) then getting it done by a properly equipped and skilled shop is the better way to take care of your wheel.
tools needed: chain whip, cassette remover socket, a big wrench for the socket, a spoke wrench, a metric tape measure or spoke ruler, a nipple wrench to fit the nips on that wheel(there are three possible sizes for such a wheel) and a truing stand.... oh, and a good instructional video of saving a wheel after a spoke breaks, knocking the true way out of whack.... then expect several false starts, a few rounded off nips, a couple choice swear words, sore fingers, and some good old fashioned trial/error experience as you do a wheel rescue for the first time..
OR... just find a shop to do it, or a bicycle Co-Op that will walk you thru the process.
it ain't easy or simple, the first thru tenth times... and then it still isn't easy, just quicker.