(Picture from Daily Buddhism)
Thank you for asking me, but you have not given your location. However www.buddhanet.net may lead you to the nearest temple.
I wonder why you want the blessed string. Actually the most blessed gift is to practise the Buddha's teachings. By practising his teachings, you will be protected. This is because his teachings stress on the reducing of all negative and hateful feelings, thoughts, and actions. When we reduce negative and hateful activities, we allow positive energies to rejuvenate our systems, thereby improving our health and happiness.