Need less non-dealer solution for changing the locks on my Nissan Altima GLE

I have a 2000 Nissan Altima GLE. 

I just had my backpack with my wallet and car key stolen.  The wallet
contained all my credit cards, and my ID & biz cards that show my
address ?which is where I park the car).  I need to change the locks
on my car and get new keys made.

The key & ignition seem to be special coded so only that particular
key works - I cannot make copies of it because it has some kind of
computer or electronic device in the key itself that allows the car to
turn on.

Because the key opens everything in the car, I would need to change
the ignition, the driver and passenger side locks, and the trunk. The
estimate I received from the Nissan dealership was about $135 for the
ignition, about $100 for each of the driver and passenger side lock,
and about $60 for the trunk. These are just for the parts - labor
would be extra. My key also came with a security device that allows me
to turn the car alarm on & off, and lock & unlock the car from a
distance.

I defiantly want to keep this security setup, I don?t want to go to a
more simple lock.

I am looking for a way to do this without paying $400 for parts and
some unknown amount for labor.

Are there other options other then what the dealership told me.

thanx in advnce,

Well you can try to search another car like yours that don't go
anymore becouse it's broken (sorry for my bad english)buy for a small
prices the pieces that you want than reassembly those pieces on your
car....
Or if the place where the car key was stolen is a place where you don't go often
ex. You lost your key in toronto, but you live in New York the
possibilities that the thief came to  New York and use the key on your
car are very,very small...
so you don't need to chanche at all...

You can have an alarm system installed with a starter kill feature. 
It won't prevent someone with your key from opening the door, but the
alarm will go off, and they won't be able to start the vehicle (even
with the key).