Heavy Bag Gloves

I Currently Have A 100lb Heavy Bag, And I'm Finding That My Gloves Aren't Protecting My Hands Enough. They Were Cheap And Without Much Padding. I Bought Them From A Local Sporting Goods Store, So I'm Looking To Spend The Extra Money And Get Myself A Nice Quality Pair To Hit The Bag With. I Use Handwraps, So I Do Have Those On For Protection Also.

I'm 5'7", 175lbs. What Size Heavy Bag Glove Should I Get? How Many Ounces?