1.- You can't say me gusto, well, you actually can, but it would mean "I like myself".
2.- Me gustÃ (with the orthograpic accent at the end) it's past tense, it means "I liked it" it can also mean "I liked him/her", it depends on the context.
3.- Me gusta is present tense "I like it" or "I like him/her".
Not everything in spanish that ends with O is masculine and A femenine.
GustÃ, gusto and gusta are part of the same verb: Gustar (infinitive), In spanish, verbs do not change acording to male or female.
Hope this is not too extensive and it actually helps you out
Native spanish speaker
Me GustÃ.....but now she's gone.
The Queso....Me Gusta!