Good luck to you, trying to learn your DSLR and photoshop at the same time, both are beasts.
I got my first DSLR a while ago and I'm still no way an expert(in fact not even close).
My advise is, spend time taking the same shot over and over again, with different isos and f-stops. If you've got a newer version of photoshop then bridge it the place to be to learn, all the info you'll need is stored in the metadata so you can easily compair them. I still haven't fully got my head around it all but this is a good place to start.
Get a tripod and remote release before you get anything else, it will be a huge help, I'm not sure if your camera has liveview or not, forgive me I'm still learning mine but if it does setup the shot using it before you make any adjustments, if using a tripod.
Trust your eye over the camera, it's better.
As for photshop, I wouldn't bother with books, there is millions of tutorials all over the internet to show you how to use it. If possible use a second computer or second screen and watch and follow as many video tuturials as you can find. I'll dig up some links to get you started.