Ah, ok - then there is time for you to do some reading & research and hunt down some recipes before your new toy arrives!
www.goneraw.com has lots of recipes, including raw icecreams made on nutmilks.
Agave & yacon (not yakon - sorry I always spell it with a "k" for some reason when not thinking) are both sweeteners.
Agave syrup is extracted from a cactus, and yacon is the tuberous root of a plant. Both are low G.I. and used extensively in raw food recipes. You can just as easily use maple syrup. It depends on each individual's own discernment.
Frozen bananas themselves can be made into raw icecream. If you have frozen them in pieces, you just let them defrost a little then add them to a food processor and process with the 's' blade. Or, you can blend them in your Vitamix, I'm sure, but may need to be more careful with the added power. You'll end up with bananas the consistency of soft serve. You could blend in a ground vanilla bean or cacao powder etc. for variations.
I'm sorry - I can't help on the leaky Vitamix, but it might just be the gasket (the rubber seal) that needs replacing?