It sounded a bit too challenging to me, so we're getting a professional mechanic to do the labor for us (mainly because of the urgency of the situation). Thank you.
Just an FYI - It wasn't the starter. It turns out the engine is frozen, and we can't afford $2,000 for another engine. Also, the mechanic did replace the starter, and there were three retaining bolts, the third of which would have normally required the engine to be lifted to get it out, but he managed to remove it in only 3-1/2 hours. I'm really glad I deferred the work to a mechanic.