"She needs food" can be written: teastaíonn bia uaithi, while "she wants food" is: tá bia uaithi, or teastaíonn bia uaithi. Tá (object) ó(subject) is always (I think) "wants", teastaíonn (object) ó (subject) is "needs" in most cases, so to be sure, only use teastaíonn when you want to say "need" not want.
Prepositions are highly idiomatic in any language and really don't match up at all between languages, so you're just wasting your time if you spend more than about ten seconds worrying about them!
The answer to your question, though, is "Yes, sometimes 'ó' means pretty much the same as 'from.'" Check out these examples: http://www.focloir.ie/en/dictionary/ei/from