meet you in one week time

First of all, both are grammatically incorrect.

I'll take the following as what you wanted to write.
"Meet you in one-week's time" or "Meet you in a week's time" for the first one

"Meet you a week later" for the second phrase.

but anyway "in a week's time" and "a week later" have different meanings

"in a week's time" = can happen anytime from now till 7 days later
"a week later" = exactly 7 days later

Your sentences are Chinglish. Proper English is

We normally say - see you in a week or meet you in a week