Need Help With Changing thermostat

well first i will list the diagnosis for any one else having similar problem then they will know what to do.
Check engine light came one (error code 128) and the inside temp gauge would not work. work what i mean by that you would have the original turn over engine to start the intail restart one the gauge would work, but when driving for a while and knowing that the temp of car should be a lot hotter than 0.
And then sometime the temp gauge would work while driving and engine light would turn off.
Thermostat replacement and or the temp sensor replacement
most generally the thermostat is only thing wrong with it.. But i purchased both just in case.
Thermostat location bottom hose the housing should have only 2 bolts to take off.
But here is the problem i cannot fit my hand down in there to get the first bolt and do not know what size fits it? I cannot get my hands down there to get wrench or a deep-well socket on there to get it off, I need some help and or suggestions on how to get it off of there.
The second bolt i cannot see from the top or the bottom of the car.
So any and all help with this would be greatly appreciated if i happen to figure it out i will be back and leave a post so others may know how to get the job done.
Thanks All, Rob