A come get me smile (or dress) is something that a woman wears when she wants men to be attracted to her. A come get me smile is one that a woman gives to a special man that is meant to flirt.
A come get me dress is one that is worn to a bar or dance that is revealing and gives a message to the men who are there that the woman wants to meet a man for a romantic connection and fast.
Sometimes it means 'come get me for sex' if the dress is especially revealing.
"Come get me, brat" is a statement that means "I am ready to fight. Come on over to me." It is a challenge. Notice the comma near the end of the sentence.