I really need a place to put all this loot. I heard you can get a plot of land.

The ability to buy plots of land is added by the Hearthfire DLC, not Dragonborn. You can obtain a house in Raven Rock on Solstheim, however. Completing a questchain pertaining to Fort Frostmoth will get you this house.

Ok cool I knew buyi g land was only from hearthfire which I have do they have a steward I can ask. I already did the Fort.

I'm a PS3 user, so I'm uncertain. I highly doubt they've added land for purchase in Solstheim, though.
When you're in Raven Rock next, you'll be approached by the Captain who gave you the Fort quest. He'll tell you what to do next.