ive fitted my new one now

i just pulled the old sony tape player and it came straight out,
then i plugged in the new one and just stuffed all the wires down a hole at the back untill it fit in all the way properly,
sounds alot beter but i need new speakers, the ones in the dash fart wen i turn the volume up too much and the door speakers arnt wired up, (they were never wired up since i bought the car).
wot size speakers do i need for the front doors?

and wot size and type do i need for the dash, dont wanna spend too much but want it to sound nice