To get those bolts off your gonna need some heat to break of the rusted cancerous flakes off to expose the bolt to use the correct socket size and get a big ole breaka bah(bar) and give that sucker a good shove. If it isn't as rusted as my imagination conjured up the get a metal brush and shave all that rusted shit off. It's very important to use the exact sized socket for the job, you don't want the bolt to be loose in a size bigger socket and slide off when you putting your muscle into it.
I would replace all the bolts.
Clean up the engine/bay and under carriage for the hell of it man.
If your gonna do it do it right. | 
