Perhaps you need to know that SIA do not recruit expats onto the 744 fleet directly.
They are not recruiting on any fleets right now as they have far too many pilots due to the delay of the A380.
They are unlikely to be recruiting again this year on any fleet and since the 744 is a 'dying fleet' they wont be needing 744 pilots again in the future.
There is a possibility of getting a contract with SIA cargo but you need to read the threads on that subject to know about the problems there.