After working with this setup awhile, it became obvious to me that I was going to need my own speaker system.
While buying your own speaker system is an additional investment, it also gives you distinct advantages...all you have to worry about is having a place to plug into; you carry just the connectors and cables you need; and you have a predictable set of equipment every show.
A DJ friend of mine sent me to a local music store he trusted.
The guy there helped me out, and I settled on the Fender Passport speaker system. (Yes, this is the same Fender that makes the guitars.) This is one slick unit -- it snaps together into a large suitcase arrangement, has plenty of inputs for different mikes and sound, and also has an option for an integrated wireless microphone. I bought the larger, 250 watt version, the wireless mike setup, and some speaker stands.
I also have a smaller Roland Cube Street, which runs off of AA batteries and is great for smaller events.