i always book tix from Airasia and no problem at all .
u can change Riggit in LCCT,(but i mostly change in town that has a better rate)
LCCT also got bus direct to Puduraya.just may not as frequent as to Sentral.
in KL I like to stay in Radius International Hotel, around HKD300+ a night include breakfast.very good location near Jalan Alor and Bukit Bintang.u can make the booking directly from their website.