Bad AAA Tow, New Tires, Do I need to pay for perfect alignment?

Hi Everyone.

I recently had a bad AAA tow and put four new tires on my car yesterday
(98 Buick Century). The garage said they couldn't align the car to
specifications because of how the tow bent the parts connecting the
rear tires (I don't know anything about cars).

The new tires have a 65,000 mile warranty and the car has 110,000
miles. The quote for fixing this was 120 labor, plus 70 alignment, plus
parts. I'm thinking about $300 total. I could get 2 new tires (if the
bad alignment wore them down) for less than $200. How many miles will
these tires last without being aligned?

They gave me the following numbers:

Rear Left, specified range (-1.4, -.4) actual (-.4)
Rear Left, specified range (-.05, .15) actual (-.24)

Rear Right, specified range (-.05, .15) actual (-.52)

Rear, Total Toe, specified range (-.1, .3) actual (-.75)
Rear, Thrust Angle, specified range (-.15, .15) actual (.22)

Basically, I figure this car will last 50,000 miles more. The new tires
should last 65,000 under good alignment. If I have to replace the back
tires once, it will be cheaper than paying for good alignment.
Can anyone estimate how long these back tires will last (how many
miles) with the above results and no fix to the alignment?

Thank you!

Sincerely,
Stephen Brown