Doable adding 5Ghz to RB2011UAS-2HnD

Dear people,
Is it in anyway doable to add in a way the 5Ghz (with an extra part/board or something) to get the 5Ghz funtion in to the RB2011UAS-2HnD board?
I’m really glad with my RB2011UAS-2HnD but I don’t want to buy an expensive new board just for the 5Ghz (if possible).
Does anyone know how to proceed?

Buy one 5GHz compatible USB dongle