What Speakers/Mixer to use for Karaoke?

[AdamChance]

I would like to get Karaoke set up at my house, but I'm not sure what kind of hardware will have to buy. If anyone could help me out, that would be great!

I have the songs on my hard drive consisting of mp3 and cdg files and that all works fine. I plugged in a rockband USB microphone to my PC and I got it working just using my PC speakers, but obviously it sounds pretty horrible.

So in order to make it sound good for home use, I know i have to buy a mixer and possibly new speakers w/reciever (and maybe a better microphone and sound card).

I have these speakers right now for my home theater, but i'm not sure if they're good enough since i heard that Karaoke can ruin some speakers that aren't designed for singing.

http://www.lg.com/ca_en/support-product/lg-LH-E932TB#

It's basically a reciever, sub, and 5 speakers. The speakers are all 155W and the sub is 255W. They work pretty well when we play rockband... so if I can use these speakers, that would be ideal since I don't want to spend any more than I would have to in order to have a somewhat respectable home karaoke setup. I know the professional guys spend a lot of money on their setups, but I just want something that will be fun for family and friends at the house.

I also have these PC speakers:

Logitech Z-5300e THX Certified 5.1 280-watt Speaker System

http://www.amazon.com/Logitech-Z-5300e-THX-Certified-280-Watt-Surround/dp/B0002SQ0AE

So where should I go from here? What is a good mixer to buy that will do the job but wont be too expensive? Should I get new speakers or will one of my existing sets of speakers work? I'm guessing I have to get microphones that will plug into a mixer because i'm assuming the mixer wont have a usb plug for my rockband mics (and maybe it's worth it to spend a bit of money on a reasonable quality microphone). And do I need any speical sound card? I think my sound card is alright because my friend built me this PC maybe 4 years ago, but it's probably nothing speical.

But I think I'm fine in terms of the software but I'm a bit lost when it comes to knowing what hardware I should buy. How much do you think everything will end up costing for a standard home karaoke setup?