Need new tires already?

I have a 2007 Nissan Xterra off road edition.  Paid a lot extra for the off road package... We got it in the spring of 2007 and it has about 27k miles on it.

So we picked up a screw in one of our tires and the shop is saying they can't patch it because of where it is located.  Not only that but they are telling us the tires on our truck are worn out and we need new tires.

It seems insane to me that we would need new tires on a vehicle that is under 2 years old and has under 30K on it.  On top of that, the husband really wants and has wanted since we bought the truck, to upgrade to a 10 plie (sp?) tire.  The shop is telling us to replace with the same tires we have on it now will be $150 per tire and the more heavy duty tire is $200 per tire.  

Here's my issue... it's December, Christmas is around the corner and we are leaving to go on a road trip vacation from Texas to Florida in a week and a half. I'm going to have to purchase at least two tires because the one has a hole that can't be patched, but I'm feeling like I got ripped off on my factory tires and I don't want to be ripped off again.

How long SHOULD an off road tire last me?  My husband is telling me that the tires are worn out already because they were designed to be off road tires and driving them on the road wears them out quickly, and yet he is also telling me that the higher grade more expensive off road tire is somehow going to last longer.  

Is this true and how much is reasonable to spend on these stupid tires?  

Tyre wear is debatable, it depends on tyre type and use, the more off road biased the tyre, the more quickly it will wear on road. Here in the UK we have much smaller and considerably more twisting roads, these wear tyres more quickly due to the constant cornering. I have replaced my tyres with Cooper Discoverer 30/70 tyres, being rated 30% off road use and 70% on road use means they have reasonable off road capabilities with reasonable road wear rates. Although an American tyre, we have a factory in the UK making them, these tyres are reasonably priced when compared to other rubber available in the UK, and have a far better life span than most other tyres.  

The Road Runner APT is a good A/T tire that should last 50k.There priced decent to.  
Dying ain't much of a livin'
From my favorite movie.
Trucks...
1989 150(200k) 33 inch hawgs and a blown 302.
1995 Pathfinder(178k)and still going with 31s.189k and blown tranny.
Bikes.
2004 Yamaha TTR 225,barly used.
Kawasaki 750 (26k) Not ran right since carbs rebuilt.
!972 Yamaha mini enduro.The niceest one I've ever seen thats never been repainted.
New 2002 f150,fx4,5.4v8,after market tranny coolers and unirol tires.

Tire life depends on a lot of things and with aggressive tires and lower pressure they can wear out quickly. Find someone that will apply a patch to hole inside tire and run them for a while. Unless it is a massive hole (like 7/16 in or bigger) it will do fine. Also 10 ply tires will not wear any longer and will ride ruffer and reduce MPG too at same pressures because they do not flex as easy so this is a bad choice here. Plys is for pressure/load rating, not tire life/wear.  

sometimes you have to be honest wiht yourself about how much off road use your x sees.the kid in you wants boggers,but really,how much dirt are you going to drive on  between tx &fl.