To become an ultrapeer, you need to have a reasonably fast connection speed & not be firewalled (ie not see the brick wall firewall icon). Providing you're not firewalled, you'll connect as an UP when the network needs UPs.

To see whether you're a leaf or an UP, click on LW's Connections tab...your connection status shows in the top left corner, just above the column headers. Yep, if you're only connected to 3 UPs then you're a leaf. If you're connected as an UP then you'll see heaps of connections to peers (other UPs) & leaves in that connections pane