You won't get better latency since the public IP's have variable routing from region to region. Your best bet is to get a static IP in the 203.135.x.x prefix, that has by far the best routing everywhere.
Ooookay. Well, I'm not too familiar with that, unfortunately. Is this something I can do manually by myself via some step by step instructions, or I'll have to get it done by the PTCL guys? It's near impossible to get them to do something like this, if the solution is the latter. :l