I was diagnosed with Sleep Apnea last April, the PLMD about five months later, on top of the Parkinson's. I take sinemet for the Parkinson's, mirapex for the Parkinson's, two at bedtime to control the plmd, however my spouse still tells me my legs move around a lot at night. I take Lunesta to help get at least 4-6 hours of sleep at night. I take magnesium, d3, calcium and potassium to try and keep everything under control.
My apnea is under control, the plmd is still there, but it has lessened siginificantly with the two mirapex at night.
You might try a time release melatonin which helps with sleep also.
The only side affect seems to be that my wife and I have really long conversations in bed, that I don't remember anything about.....
Hope you get it all under control.