Max volume?

Ok so i just got my new headset with mic, heres my problem.

Before getting this i used mic, headset and speakers, i would plug the headset into the speaker so i could have much higher sound.

Now that i got this new headset with mic i cant, need to plug it straight to the pc since the red and green input thingy are close.

So is there a way to turn it up more than its already at?

Maybe a sound driver or a program that would do it for me.

Some of you might not know what im talking about and i dont blame you, im horrible at explaining my problems ^^