Welcome, Joel!
You can use the same pot for boiling and mashing, but where will you keep the wort while you clean the pot from the mash? What will you sparge into? In my opinion, it is best to have 2 vessels for mashing and boiling. I use a cooler mashtun, and a 10 gallon pot for boiling.
As far as a higher alcohol beer, there are several ways to boost your abv... Use more grain/extract. Or use less water. I sometimes add some plain table sugar, it helps to dry out the beer, and adds to the abv as well. It could be important to make sure you have a yeast strain that is tolerant of higher alcohol content if you want to go really big...