3D Level and Vehicle Design in Unity3D

Hello we need some support during our Unity 3D Game development. The game is about a car/vehicle that should drive throu a terrain with hills, drops and obstacles. The game will be rendered in 3D but The object will not be able to steer left or right. I need someone who will do the following tasks for us: 1. model/create 3 levels with about 60 to 90 secs time to move throu the level. 2. 4 vehicles for those levels are one truck, on jeep/monster truck, a tank and a buggy. 3. The vehicles and levels Mmst be imported to Unity 3D and configed there. We already have a script to drive and steer the vehicle. From the project order, we need first of all only 1 vehicle - the jeep/monster truck and than the first 2 levels. After those levels are done the vehicles and after that the later level. Looping forward to read from you.