half ironman in miami

I'm looking for some coaching/direction, I've got about 6 weeks left before this race an I'm looking for some help, starting off (I'm poor/little to no $ for professional coaching) so I'm doing this on my own. My swim time isn't fast but I can cover the distance within the max time allowed, I'm good with bricks and I can cover about 8 miles in 11 minutes per so far and biking is doable. My question is how do I get it all pulled together and what should my diet look like from here to race day. Carbohydrates are on my plate most nights and fruit and veggies are with me through the day,,,,I realize I'm asking a lot,, but at 54 yrs old and entering my first ever race (a tri to boot) I'd really like to finish and within the 8 hours if possible. Is there anyone out there that can lend me some advise. Most my friends are assuming I will die on the course and I'm determined to prove them wrong. Thanks in advance and I can be reached at [email protected].