Road bike advise primarily for Durban 70.3 next year

[breaker]

So I'd like to take on the 70.3 next year in durban and need to get a road bike. I do not do much road rides, but clearly going to have to change that. Also would be nice not to need to borrow a bike for the likes of the Argus as well.
Starting with the budget/bike spec, what would I be able to get away with R5k,R10k,R15k? I'm clearly not going for podiums in any of the races and previously I've done the argus and cape town ITU  on old Raleigh RC 2000 that have been to small for me (52). 

Any recommendations of what I should be looking at? 

Obliviously I'd like to keep the budget as low as possible because I also need to buy a wetsuit, but am not sure if buying cheap is the same with a MTB, ie gonna regret it later?

[Breezer]

Look at something like this. Secondhand, but a full carbon bike with a very reliable groupset and wheels.

 

https://www.bikehub.co.za/classifieds/250535-silverback-strela-concept/

[rudi-h]

If you're serious about the sport, rather look at the upper end of your budget i.e. the R15k bracket.  That's going to avoid buyers remorse and upgrade syndrome...  Those two phenomena have costly consequences a year or two down the line.

 

I agree with breezer, if you can get a 2nd hand carbon frame with 105 or better components you won't be needing anything better for a long time to come.