How to obtain a complete frequency band from two sub-bands in an EEG signal?

Hi there! I have used WPT for eeg alpha(8-12 Hz) and beta(12-30 Hz) band extraction, and it gives me alpha band in two sub-bands e.g. 8-10 Hz and 10- 12 Hz, same persists in case of beta band where i am getting 3 sub-bands. The problem arises in joining these sub-bands to form a complete frequency band. Anyone! please help me in joining these sub-bands so that i can get a complete frequency from 8 Hz to 12 Hz for Alpha band. It will be of great help to me...