Issue with iMac and iPad 2 (fighting over IP Address)

Hello fellow Mac users,

I am a newbie to this forum and was hoping someone can shed some light on my issue that has been lingering for about two weeks now.

Hardware:

iMac (mid 2011) MAC OS X Lion 10.7.3
iPad 2
Motorolla SB5101U SURFboard Modem
D-Link Router WBR-2310

Issue:

A few weeks ago, my iMac pretty much started the "Self-Assigned" IP Address issue out of the blue. I took my Mac to the Apple Store and of course the wifi connected flawlessly to the stores router with no issues; yet the problem persists with my home router.

I've completely a bunch of steps for a possible solution with the information that I found over the internet to no avail. I have:

• Hard reset my D-link router and re-configuring it using a WPA2 security.
  
• Restarted my modem/router hundreds of times.
• Renewed IP Address
• Did the Terminal procedure.
• Tried to find the plist file that Apple Support mentions but its not there.

Temporary Solution:

So today I used the iPad2's IP Address since that and the ps3, and TV were able to pickup the wifi with zero issues. I manually entered the IP Address, DNS, Router, Domain, etc. and it worked finally. BUT now my Ipad2 will not link up to the internet and after a recent update, it is stuck in some reboot mode.

Can someone please help me sort this issue out?

Thanks.

Update

Looks like I figured something out. I basically reset my router again and then allowed my Ipad2 to use the automatic IP Address it was being assigned. I then went into my iMac settings and gave it a random IP Address by adding a few numbers.

Everything seems to be working now