Oh, and also, I disagree with oal4n.... i've got a pair of tri shoes and use them for everything... I haven't bothered getting a pair of bike specific ones.... and haven't suffered as a consequence either.
If you haven't got a pair of bike specific shoes,how do you know you haven't suffered as a consequence?
Whilst you may have have finished a couple of sprint triathlons - a time of 2hours 44mins suggests very little training was done. Don't waste your time fantasizing over a completely unrealistic target of completing a half iron man if you aren't prepared to put the effort in,. Start doing parkrun regularly, get some miles on the bike (get a road bike too) and aim to improve that sprint triathlon finish time by an hour by this time next year. Now that would be an achievement that you could rightly be proud of.