Car Speakers!

I have a Suzuki Margala, in which I have 2 Sony Xplod speakers at back, and 2 small speakers in the dashboard...but now those speakers are ruptured due to sun heat and old age.

I wanted to know what would be the best place to buy same standard sized speakers and get them installed, and around how much would it cost me.

and any special brand and model of speakers recommended.