Not sure if you are DIY kind of person, not sure based on your missing the exhaust manifold bolts on the first glance.
What you can do is what I did, I installed clamps rather than trying to remove the broken bolts. I had both rear bolts break on my truck.
The clamps are cheap, as I recall, one is much tricker to install than the other, I do not recall what side was the biggest problem.
You might be able to find a shop to install the bracket for about 1-1.5 hours at tops?? It is not a good idea to let these stay broken, it just will cause the others to fail quicker.
Not sure if it is a good idea to try and remove the non broken bolts??? Might be best to leave these alone. I would want to speak with someone that has a lot of experience removing the bolts. Do the others usually break or can they be removed one at a time without worry of them breaking.
See these clamps, there are 2 version, one for each side of the head.
I have not tried the Amazon/Dorman ones, they are cheaper than the ones I purchased which are listed below the Amazon links.
https://www.amazon.com/DORMAN-917-107-Exhaust-Manifold-Clamp/dp/B00GHT9L4O
https://www.amazon.com/gp/product/B...rd_wg=wIs8s&psc=1&refRID=JPXXF4CZ7TFQ80CMS1GR
These are what I used -
http://kralautoparts.com/
The next thing you need to worry about is the rusty brake lines!!! A SERIOUS safety hazard!!!!!
The replacement lines are about $75 on Amazon, they take a few hours to replaced, but it far wiser to replace the brake lines on YOUR schedule then when they blow out when trying to stop in a tight situation.
ALL of the late 1980's to mid to late 2000's models have this problem. TRUST me, if your truck falls in this window where the brake lines were problems and you live ANYWHERE other than say Arizona or New Mexico where there is no rain or humidity, the brake lines need to be replaced!! Usually between year 9-11 on most of these vehicles.