All Eyes on Me

Any jewelry store (or even art store) should sell clasps for between 1-5 dollars depending on how nice you want it. You should retie knots around that and tuck the extra wire under the pearls next to the clasp. I would recommend a lobster clasp (with a 'hook' that goes through a loop) because it looks the most like you bought it and is most likely to stay.
Also string with knots might be better for pearls...