If it were the former, I would personally say "Эта женщина - мама" = "This woman is (my) mum". Your version is less likely, but the original sentence is also extremely unlikely -- not grammatically, but content-wise. So, basically, outside of any particular context you cannot tell the two apart based on pronunciation alone.
"мама, это женщина" I think. The dash is used sort of as a colon. You could in a way directly translate the sentence as "mum: woman". Since Russian doesn't have the word "is" it uses the dash to emphasise that something is something else. If you use a comma instead the sentence is interpreted as "mum, this is a woman"
i have a huge problem with transliteration. i don't know how to write in cyrilic because i have no idea how to install the cyrillic. I am 80 and don't understand many technical things. i transliterate using french, my mother tongue but it it not like the english transliteration. so i am blocked and cannot continue srudying russian, unless i find a french-russian/ russian-french course ! too bad. I can read cyrillic and write it fluently BY HAND, but not on my laptop.