You mean Eäranë? For ä, put Num Lock on, hold Alt, and punch in 132 on the number pad on the right of the keyboard, then release Alt. Do the same for ë, but with 137 instead.
When I do that with my full name, I get Angrod Súrion. My nickname and my last name gives me Aranel Súrion, and my pen name gives me Aerandir Telrúnya. Angrod is the name of Galadriel's elder brother and is Sindarin for Iron-metal, and Súrion is Quenya for Son of the Wind. Aranel is Sindarin for Princess, but also Quenya for noble star. Curiously, it appears as a title of Dior, Beren and Lúthien's son. I think I'll scrap that one. Aerandir was a mariner that accompanied Eärendil, and his name is Sindarin for Sea-wanderer. Telrúnya might have a Quenya meaning as perhaps Last Red Flame, or Roof (of) Red Flame. I believe it was inspired by talrunya, which means the sole of the foot.
Most of these names aren't really original, so I'll just stick with [u]Tyrhael Idhraen [/u](Powers (of) Wisdom / Wandering Heart), or some derivative, for my Sindarin name, of which the surname will probably change several times anyway.