New Headunit, And Possible Speaker Update?

[Zmithy]

Firstlyy, I'm brand new to these forums so Hi in advance!
And secondlyy, i'm a total noob when it comes to anything speaker related.

I've got a P Reg Polo 1.0 L.
And i know for a fact that the speakers and head unit suck.
It has the basic casette player that it came with and has 4 speakers in the front and none in the back.

I'm wondering if anyone can help me find a decent head unit that will play mp3's and CD's and i'm looking for a speaker upgrade for the front four speakers. Might look into more speakers for the back and a sub at a later date but all that sounds complicated and expensive for the moment.

So yea, any recomendations on speakers and headunits? Price range of around £150
Any help will be appreciated.
Cheers.

[Tim_GTi]

Do you have £150 to spend on both speakers and headunit?