What's up with this wire harness?!

I went to my local vehicle audio retailer and bought myself the essentials for installing a new head unit. When I got home and began to install I was mortified to find out that my wire harness did not fit into my car's harness. I went back and they insist they gave me the correct one, then I went to another store and they said that it is indeed the right harness. So now I have no idea what to do, and there is no resource online to help me with this problem. Can someone give me an idea of what is wrong with this? I've provided pictures:

http://i7.photobucket.com/albums/y286/Carmeles/IMG_0334.jpg
(Harness that I bought from the store.)

http://i7.photobucket.com/albums/y286/Carmeles/IMG_0333.jpg
(Built into my car)

Looking at these pictures you can clearly see that the prongs are two completely different shapes; Flat and bowed type prongs are in the car and the perturbing needle prongs in the one I bought.,

you left out some VERY important information .... what car and what type of OEM stereo. Looks like one of the hranesses is for the standard stereo and one is for the premium sound system.

you left out some VERY important information .... what car and what type of OEM stereo. Looks like one of the hranesses is for the standard stereo and one is for the premium sound system.

Oops, my apologies. It's a 1990 buick custom century. As for the stereo, I won't be able to say until I'm home from work, sorry. :(

look like you need the one on the top .... http://www.installdr.com/Harnesses/GM-Wiring.asp

maybe something like this .... http://www.crutchfield.com/p_120701677/Receiver-Wire-Harness.html?tp=2977

It's an older harness. My friend had that one on his 1985 Blazer. The one in your first picture is on the mid-90's cars, like my friend's 97 Cavalier. I think even my 89 Astro had the newer harness even. You need to get the harness for older GM vehicles.

At least you have a harness on your Buick, they cut mine. I'll just have to test the wiring when I feel better and it's not cold out. I'm using a USB power adapter with some computer speakers in my car for now. Just have to find a cheap stereo to put in there.