Either replace the PVB with RPZ (if you can affort the $$$ and pressure loss) or a Dual Check (if local codes allow), or install a 2nd mainline up to the balcony and install a 2nd PVB there (i.e. tie into the main line BEFORE the existing PVB). The other alternative is to rerun the main line upto the balcony, move the existing PVB up there, and return the line back to where it came from.
Only other alternative is to connect with a garden hose. Basically, run a water line up to the balcony and install a hose bibb (make sure you can drain it for winter is running on the exterier). Then use the typical setup of drip irrigation from a hose bibb. You make sure to place a vacume breaker device on the end of the bibb, and then use the simple check valve back flow preventer that comes with drip kits. So long as it's not a permenant install, that setup is perfectly legal (in most places).