Well, the simple answer is you need to catch up on the neglected maintanance items. Unfortunately, even going down tommorrow and having all the neglected maintanance services down may not extend the life of the vehicle as damage may have been done due to the neglect. Most people unfortunately believe that the maintanance services recommended in their owner's manual is as way for dealerships to make money. This simply isnt true. These services are recommended at specific intervals by engineers who design the vehicle and know what limitations are for the different fluids and components.
Specifically, you need to have the transmission serviced ASAP- once it turns 100K miles without ever being serviced, you wont find a shop that will do a transmission service on it. This is due to the odds greatly increasing that after the service, the transmission will fail.
You need to have the cooling system flushed, the brake fluid flushed, and the power steering fluid flushed.
The air filter needs to be checked and replaced if needed.
The serpentine belt and all cooling system hoses need to be replaced at this point.
I would also recommend having a direct induction cleaning done on the fuel injectors and throttle body.
Beyond that, the suspension and steering components need to be checked, the brakes, the charging and starting system need to be inspected.
Once you have all the maintanance services caught up, you need to stick to the recommended services at their recommended intervals.