The first expansion will be released in Europe on September 6th and will no doubt cost a few pennies. The expansion itself is called "Weapon Master" and consists of five survival modes that require you to utilize limited weaponry to defeat as many opponents as possible. The second is entitled "Speed Master" and consists of five more levels where you must defeat your enemies as quickly as possible. The final expansion will be called "Rachel Master" (Oi, you in the back - stop sniggering) in which you play as Rachel in five levels to become the "World's number 1 Fiend Hunter."
There's no word on release dates for the latter two expansions, nor on any sort of pricing structure. We'll keep you updated with any announcements regarding American release dates, when we hear them.