Increase Item limit in houses

I've been working hard on my dream house and it is almost done. The problem is that I can't add any new items. It keeps telling me that I've hit the item limit.
Every time I host a party, I need to move some things to storage just to be able to add the party items.

I've also had to put all of my heirlooms and other non-essential things into storage. There is just no room for them in a well decorated home.