Service Dpt. got troubles repairing my mac and give me alternative options.. What option should I choose? Help!

I got a MacBookPro few months ago (October 2011)

17-inch, Early 2011

Processor 2.2 GHz Intel Core i7

Memory 4 GB 1333 MHz DDR3

Graphics AMD Radeon HD 6750M 1024 MB

Software Mac OS X Lion 10.7.4

But for multiple issues I had to take it back. After several repairs, they offered me the three options below as the 17-inch MBP is discontinued(?).. Which one should I choose?

The main reason I want a 17-inch screen is that I am working with graphics and also I move often, so I can't afford carrying an iMac around.

1. Replace the unit with this 15-inch Macbook Pro - this would take approximately 2 weeks to arrive

15-inch MacBook Pro

2. Replace the unit with a 15-inch Macbook Pro Retina - this could take approximately 4-6 weeks

15-inch: 2.3GHz Retina display

• 2.3GHz quad-core Intel Core i7
• Turbo Boost up to 3.3GHz
• 8GB 1600MHz memory
• 256GB flash storage¹
• Intel HD Graphics 4000
• NVIDIA GeForce GT 650M with 1GB of GDDR5 memory
• Built-in battery (7 hours)²

3. We repair your unit in store as soon as possible.

Can you help me out please?

1) I am afraid that if I choose the third option, I won't be able to fix my MBP in the future in case that there are no spare parts (for example, if I get problems with the screen).

2) I don't understand how equal are the three models based on their prices...