Obstacle avoidance with an UGV -HELP PLEASE-

The reason I posted here was to get help improving the algorithm!! Is it possible to use for loops to improve the algorithm? My current setup with this algorithm works well with hallways and enclosed spaces with walls. I'm going to have to buy longer ranged sensors soon, but my main provider is out of stock! And I'm not entirely sure where I will mount them.....that block of wood in the front actually adds a lot of weight and makes it hard for the car to steer if it isn't moving--maybe I'll buy a more powerful servo while I'm at it.....

And wildbill, I've tried starting there, and I've also made a post about that, but I've had no one really help me with that, and everyone is saying my GPS will not be accurate enough, and that I'll need to set up GPS differential--but I plan on saving that for the next model of the robot. Is there any way you'd be able to start me off with the basics of going from point a to b? And doesn't that require the use of interrupts? I started to use interrupts and I've not been very successful--Is it possible to have all the statements in the same main loop instead of having to use interrupts?

-Matt-