I think it's worth pointing out again that adding a controller is not a silver bullet for roaming troubles. The controller will only add 802.11r/k (and with 9.9, v) fast roaming extensions, but will not necessarily force clients to make better roaming decisions, and will only make a difference to clients that actually support these roaming standards (such as iOS 7.0+ devices)
The majority of roaming issues are solved with smart-roam or client-side settings (for Windows clients that allow you to choose roaming settings), and not making your network overly complicated (like mixing a 300mbit and 1300mbit device such that the best roaming decision is no longer a simple matter of choosing the strongest signal).
Since a ZD1100 is quite pricey for a home user, you probably don't want to get one then feel disappointed it didn't accomplish what you were trying to do. The money is much better spent switching out that 7372 for a R600, or adding another one if borderline 5GHz coverage is yet another reason why clients are making a poor vs poorer choice when roaming.