Introduction (I am going to write in Hiragana but please correct with Kanji or Katakana if necessary

こんにちは！わたしはじりあんです。あなたはitalkiですか。よろしく。

(みんあさん) こんいちは！私はジリアンです。宜しく(お願いします)。

1) In brackets I've written "minna san" which just means "everyone". It's not necissary for your sentence but you can add it if you'd like :)

2) Watashi has it's own kanji
3) You should always write western names in Katakana ^_^

4) Yoroshiku is totally correct, but It's more polite to say "yoroshiku onegai shimasu". 

I'm not sure what you were trying to say with "あなたはitalkiですか" But It says, "are you Italki?" I can translate the sentence you originally wanted if you'd like if you can tell me in English! :)

Keep up the good work! ^_^