Give a better currency rate

I used to convert my Singapore dollars into foreign currency with my bank. I learned recently that the spread (i.e. difference between the buy and sell rate) is about 1.3% compared to 0.3% charged by an online stockbroker. The difference of 1% is for a two way trade. For one way, the difference is 0.5%.

If the amount is $100,000, the difference in charges of 0.5% is $500. I have to pay a TT fee of $10, so I can save $490 by going through the online stockbroker. I hope that my bank can give a better currency rate, so that I do not need to go through another source (which is quite troublesome).