You can hire Hirelings for the in-game currency (Platinum, Gold, Silver, Copper) as well.
There are, however, several "levels" of Hireling contracts : The "Gold Contracts" must be bought with the Turbine Points, but have the advantage that the Hireling can be "summoned" deeply within a quest, whereas the normal contracts (those you buy for Plat) can only be "summoned" at the Quest entrance.
Edit : I think with the Gold Contracts you can even have more than 1 Hireling, no ?
And yes, I do plan to buy a headset, too. I think next month (isn't far away anymore ), but I really don't know about quality of headsets ?