Going Zwei, but don't know what to get

[Mr.Peso]

Depends on what your money situation is like.

For a start a Heavy War Hammer (~2,5-3 mil) is pretty good. Cheap 2H Swords are allround crap.
If you can afford something pretty I'd suggest a Stone Maul (5-6 mil) and/or a Forlorn Hope (Should be around the same price).
If you want to go legendary get a Legacy (~ 25 mil)/Durendal (40 mil)/Mjolnir (30-35 mil). All the 3 are amazing weapons and get you to the point weere you can dish out the max damage you can achieve.

I'd also strongly suggest you not to forgo shields. SKS is a must have if you cant afford something better, else go for a resilience/Studded Steel Shield.
As a Zwei you will be forced to shield more often than you want so better bring in something to help out there.