How to translate "for" in Farsi

I haven't seen him for one week
يك هقته است كه من او را نديده ام
/yek hafteh ast keh (man) u: ra: nadideh am /

I = subject
Haven't seen = verb
Him = object
For one week => Let's accept this phrase as our 'time' in all sentences.

for one week
يك هقته است كه /yek hafteh ast keh /


one week
يك هقته /yek hafteh/

other help words
است/ast/
كه/keh/