Well, they are different forms. "kobietę" is Accusative singular. "kobiety" is: Nominative/Accusative plural, and also Genitive singular (most feminine nouns have those three forms identical). So you need to know which case is needed by which verb/preposition/construction.
I think you have to use the question word "czy":
-Czy znasz tamtą kobietę?
-Znasz tamtą kobietę?
I heard both versions, not sure if both versions are correct. If somebody from Poland can tell this would be nice :)
This was so confusing to me, I've always thought that to make any form of "this" become "that" I just needed to add "tam-" as a prefix. Apparently this works for every form except the feminine singular accusative lol