Help my sync problem or the kittens die!!!

Firstly, I apologise for being an insufferable nOOb. Quite frankly, if I knew the answer to this inquiry, personally I wouldn't post a reply to this thread because I hate people who can't work out basic stuff for themselves (or Google it), and I'm scornful and unhelpful like that. But I'm hoping you'll be nicer than me. Pleeeeeeease.

I have had an iPad3 since its launch, and in the last week have bought an iPhone and an iMac. Yes, I have come over to the Dark Side. It's oh soooooo cool here, but I'm having problems finding my way around.

Here's my problem>

When I got my iPad, I connected it to my Dell laptop PC, set it all up with iTunes, and backed it up and synched it and everything. No problems. Now, however, I want my three Apple devices all in bed with each other in a mutually consensual and orgiastic relationship, which is mostly why I came over to the Dark Side.

But it seems that I cannot get iTunes on my iMac to play nicely with my iPad OR iPhone, as it says my iPad is already linked to another computer in iTunes. Looking into this, I see that you cannot have devices registered in iTunes to more than one computer- presumably in order to prevent people unlawfully sharing copyright material.

I Googled this like a good little nOOb, and found out about de-authorising computers. I did this for my iPad on iTunes on my Dell laptop. I even uninstalled my iTunes program too, for god measure, but when I plug my iPad and iPhone into my iMac, it still tells me they are owned by my other computer.

HELP! Pleeeeeease! Or I will kill some fluffy kittens.*

* not really. No animals will be harmed in the production of this thread.

 

Okay, I'm sorry about the useless verbosity of my OP. (FWIW, I was trying to make it funny for the sake of those kind enough to read it, rather than for my own health.)

Thanks for the advice. I do not wish to sync with two computers. I want to sync with my new iMac, but I cannot do so because the iPad and iPhone are tied to my Dell laptop, despite my de-authorising the iPad and uninstalling iTunes from it.

Any ideas would be most appreciated. Seriously.