Translations

How would I say "Take Care" and "You're Welcome"?

"Take Care"

Casually: Ki o tsukete
Politely: Ki o tsukete kudasai
Very politely: Oki o tsuke kudasai

"You're Welcome"

Dou itashimashite

Some non-Japanese speakers use Take care as "kiwotukete" on E-mail.
If you want to use it as an expression of parting in real life you can say "kiwotsukete" but not on the E-mail.
If you want to use it end of the E-mail, simply use "jyane"or "matane" instead of use "kiwotukete"
My English is not that great, I hope you understand what I trying to say.

take care (jya-ne)
momoko

------How would I say "Take Care" and "You're Welcome"?-------

Many different ways to say it, depending on your context.
if you're expressing these two phrases together then what you're saying here can go like this.....
ご連絡ありがとうございました。
gorenraku arigatou gosai mashita.
(acknowledging thank you letter)
お元気で。
ogenki de.
(take care)

*previous poster's expression
じゃあ　ね。
can be
でわ　また。
それでは　また。