Sometimes it's hard to give our kids "tough love," but this seems like an appropriate time to do just that. Your daughter has demonstrated that she has the ability to sit at the table, use her silverware & eat like a big girl. Before each meal, sit down with her for a minute and review your expectations for her behavior during the meal. Explain to her that if she gets up from the table, or refuses to use good manners, she will be done eating until the next meal. The hard part is going to be when you actually have to take her plate before she's finished eating. It won't hurt her to be a little hungry - and she will realize that you mean business.
The rule we use at our house with our 1, 3 & 4 year olds is just that...if you get up from the table or don't use good manners (we usually give them ONE reminder), you're finished eating until the next meal. Our 4 year old (girl) had her plate taken 3 or 4 times, then she realized she would rather have good behavior & eat, than have to watch everyone else finish their meal while she was still hungry. Good Luck!