Hiya,
First of all to clarify, a DCA malaysian PPL is recognised in most countries as long as the country is ICAO. Singapore is an ICAO so is malaysia. Therefore the 2 countries recognises each other licences. But in most countries, they will still require you to do an Airlaw paper and pass a flight test by the country issuing the licence. Hope this clears up the issue.
Secondly, which club to choose from in johor? The best answer is to go down to those clubs and do your homework. Do you want to have good club atmosphere? Do you want cheaper or more expensive hourly rates? Do u prefer ex air force instructors or civilian instructors? Do you want to pay monthly subscription fees or not? Do you want to start flying in a c-172 or a c-152 or a c-150? Which of course comes with different pricing.
Weigh all this first, then decide which club is best for you. Hope this helps