Audio Amplifier and Laptop

I am not familiar with audio thingy, so I have to ask some questions before I get myself an audio amplifier. My situation is like this: My bro gave me a panasonic DVD player with home theater system (5 speakers + subwoofer). The DVD player has karaoke system in it. But to activate the karaoke system, I have to change to Disc option.

Now I want to connect my laptop to the DVD player (AUX1) and output the sound from the player. When I change to AUX option, the karaoke system won't work.

My friend told me I should get an audio amplfier so I can plug in the laptop and microphone into audio amplifier and output the sound together through DVD player's speakers.

Is it possible to do in that way? What kind of amplifier I should look for?

Thank you.