A private lesson is not going to help you with this dog's issues, if you don't have even the most basic of obedience training done. There is a plethora of information on training on this site. There are videos all over the web that can help you teach your dog basic house manners. Off leash is not an option until you have the dog under control.
Don't wait for the class to teach your dog. (that's not what they are there for, they train you to train your dog) Don't use a prong or E collar until someone shows you how to properly use them. If your dog respects you, you will have no problem getting him to sit/stay while you break out the broom and sweep up the mess he made.
If the other dog is 'lazy', he is the one that should be separated, with a kiddie gate. Does your dog know not to bowl one of those over? Training 101, boundaries. When you crate him, have a reserve of stuffed Kongs in the freezer and give him one. Only use them when you crate him, then the crate becomes something pleasant and not the county jail, no one likes the county jail. (stuff them with NATURAL peanut butter, kibble, shredded carrots, oatmeal, whatever you have researched to be safe for dogs)
Simon, who came to me at 1 year, was what I will call a bronco. He spent the first year of his life in a 10 x 10 and was completely out of control. He saw 2 trainers and a behaviorist and was not permitted into any area classes due to being deemed 'dog aggressive' (not to mention the whole 'I really hate testosterone' deal) I had him living peacefully with 2 other dogs, 3 cats and a pig, within a month or so. I have been training him myself, without the use of any harsh punishments, only praise, and he eats it up. I seriously think, if he could, he would turn a cartwheel for me (unless there is a man around), because I earned his respect. If I can do this, at my ripe old age, you can start teaching your dog basic house manners. Be kind, be fair and you will make headway. A strong 'leave it' command is essential, start there. Don't issue a command (like Tim has said over and over) unless you can enforce it. If you are losing your temper with the dog, breathe and step into his shoes/paws. Keep it simple, they don't think like us.
*I would like to note, that Simon's man aggression is something I don't know how to deal with. I truly think this dog is a complete wackadoo. I know I need professional help with this particular behavior, but private lessons are not an option, there simply is no money for them. A this point, it's simply management and muzzle.
No beast so fierce
EPI, man aggressive, ball crazy, fearless protector, my heart