speaker help pretty mega please

[Dreadi]

ok so i found out one of my speakers is duff the other week when i put in my cassette radio which is used to run a tape adaptor for my zen.
i know the sound quality is power from these (i think) but would new speakers help?
this is the speaker i pulled out, 4 inch rear left door speaker

and this is the connector

now would i need to re-wire and stuff to fit new speakers ???
also could you spec me some, i dont want to go mad as its for a beat up 93 reg 106 but i want something that sound good and has as decent base as i can get on a tight budget without an amp (altho i know nothing about this stuff)

suggestions ?

 

[Dreadi]

thanks for the help then guys.

about th 6x9's, can i run them without an amp as i'd rather full the ugly holes in the shelf?

will the wattage output fro my HU by on the top of the unit on a sticker or something ?

 

[Dreadi]

says nothing on the front but a quick google brings up this
25watt