Need Helvetica LT Std font

I'm trying to update company business card files for reprinting. The font is Helvetica LT Std and it's not available on my system (Mavericks). These were originally designed on a PC and I don't want to have to redo them entirely, just edit. Anyone know where I can get a Mac version of this font? And then point me to instructions on installing? Thanks in advance for helping me save a beautiful Saturday!