Hi I do not know where you can get the service, but I myself am interested in jewlery designing recently...
You can try DIY... I know there is a store at People Pk Centre Level 1..
very HUGE range of jewelry findings.. I know there is one at Dolby Ghaut too.. but PPle's pk price is good & BIG!
20% & buy 1 get 1 free!!! I saw lots of accessories that you can work with your Swarovski.