dude! didn't you do any homework before you take the little guy home?
about caresheet: I am sure its everywhere, just type sulcata and you should find it, checkout some of the main sites: sulcatastation, worldchelonian.org, tortoisetrust, tortoise.org...also, i'm sure there's quite a few sulcaltas in this forum so keep scroll down.
about diet: he will never get tired of them lettuce you're feeding him right now but enventually will die because of it if feed alone, it's like asking the kids if they ever get tired of ice-cream! I would cut that craps asap and give him something appropriate like dandelions, timothy hays, cactus pads...just BECAREFUL about pesticides if you give him lawn grass or anything in your local parks or someones else's.
about heatting: they needs both above and below if you could accomodate that set up (at least the top one), a heat gradient between 75 to 100 degrees so he can choose his own spot but be cautious about them heat pads and how you arrange them so that your bambino won't get cooked incase he flipped over .
you still got lots to read so start digging!
and last but not least:
...enjoy your little "EXTREMELY TINY GUY"... while you can..!!! .