Really all we need to know is...

1) How far away do you want to listen?
2) At what level do you want to listen at that location?
3) The sensitivity of your loudspeaker of choice.
4) The power handling of your loudspeaker of choice.


From this data you can calculate how big an amplifier you need to drive these speakers at your given level at your given distance. Now, if your speakers cannot handle the amount of power need to reach that level based upon your specifications, then it's time to look for a new speaker. This is probably your entire problem in a nutshell.