Reupholstering will not do enough. Paint the chairs and table is some fashion.

I suggest painting the table and replacing the chairs.

The new light is very modern and very pretty, looks like you have also done some lovely modern updating in the kitchen. Problem is the dining set you have is very very very traditional and is clashing with the new modern elements. No matter what material or paint you use on the chairs they are still going not going to have that clean simple modern look you are going for. Since it is a good quality set in good condition, sell it to someone who will appreciate it's lovely traditional look and use the money to buy a nice modern dining room set that will fit the rest of your decore.