I have a mac and I don't know how to get any of these on here. I know there are other forums but I can't find them. I just don't know how to do any of it. I know there is some way I just don't know how.

You could try running Windows on mac using Bootcamp and install GTA IV/LCPDFR. But mac is not made for games such as GTA IV. You should either buy gaming laptop or build your own gaming desktop. 

I highly recommend NOT installing GTA on a Mac. I have tried it before, and it just does not work. The graphics cannot handle GTA. If you still want to try it though, you will need to install Windows using Bootcamp, and then install GTA.

How bad do you want it, because if you really don't care all too much, I'd say not to even bother. The game requires a ton of resources (most Macs can't handle the game's demands), you would have to install Windows, do a ton of updates, install Steam, install Grand Theft Auto IV through Steam, install LCPDFR, while running pretty much everything as Windows Vista SP2. Even after doing all that, the chance that your game will launch is 50%, and the chance that LCPDFR will start is around 10%.

Hate to beat a dead horse here. But now that GTA IV is available through the Apple App Store is there a way to get LCPDFR? I have read a ton of posts and threads here most with people insisting a Mac can't handle the game which is far from correct, or claims that GTV IV is only a PC game and one would need to use boot camp to run it via a windows install wich is also incorrect. That all being said I would really love to be able to use this mod for GTA IV if it's possible.

Obviously people are anti-Mac here, I'm using a Mac to play GTA IV and it can easily handle it, it's not their primary role but it manages very well. The way to go about it, which is a little complex is to use BootCamp to partition your Hard drive. There are plenty of videos on YouTube which show how it's done. Once you've done that it works exactly like a Windows machine. But I warn you, whilst I love my Mac, a custom built gaming computer is far more suitable and performs better for the same money.