J.T.
Hi M.,
I have a daughter who "wouldn't apply herself" but was very smart. After a high level of frustration and doing some research and testing we discovered that she had some had some "learning issues" caused by some underlying input (eyes & ears) processing problems. An underlying input processing issue means that the input into the brain is not interpreted correctly e.g. dyslexia. So have your children's input checked (ears and eyes). A developmental optimitrist will check if the brain is correctly processing what the eye sees. You don't want an optimitrist who will check if your child can see letters on an eye chart. You also want an "audiology" test not a "hearing" test. An audiological exam checks if the brain is processing the ear input correctly. A hearing test just checks if the child can hear a sound. Very different.
The best thing to do is to begin with an educational therapist or neuro-physcological exam (checks how the brain effects behavior) if you can afford it. Also check out "interactive metronome" (just google the term) for ADHD. also check out the "lindamood bell" site which has programs that help with "comprehension" not reading. Everything they do is based on research into how to improve comprehension. If you can't afford the interactive metronome therapy to help with the ADHD then you can buy one of those dance pads that attach to a game cube. The idea is to synchronize the brain and motor movement which helps with ADD.
We tried using tutorial services and found it very expensive and ineffective. Tutorial services in my opinion are based on the premise that "repetition" will help, but not if there is eye to brain processing issue!
Please be aware that there are some people who believe that the therapies we used are "quackery". If you are interested in persuing this further I'm willing to privately send you a list of resources/contacts that we used.
Hang in there and keep looking, and believe that your efforts will pay off.