A Q about Digital keyboard plz !try to help me ?

[Gayret]

Hi everybody,  


Recently i bought a Digital Yamaha keyboard  
i only can play a few basic sons which i learned  5 years ago, after that i didn't practice at all because i was so busy with my Med school . i only like to master electronic keyboard from basic to intermediate level. can anybody here can advise me how to start !

i am thinking to buy a softwear for this that  i can study by myself i heard there are some very good video lectures on CD they teach how to play but on the market there are so many so plzzzz  

advice me which one i should spend my money for or how can i improve myself i also have to learn to read music s**t .

thank you very much!

God bless you all.