there are quite a few older posts on this. you might want to search for 'clothes' to see some of them.
In the meantime here are some online options, and there is always the asiaxpat classifieds :)
You might want to look at these two shops you can order online from Singapore:
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Or Online from Taiwan/HK:
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(they have some nice items on sale right now!)
For Bras, international orders are easy at:
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For a very comfortable bra:
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(Essential Bra and Leisure Bra - inexpesive and perfect for nursing)
The site is in Chinese, but has lots of English and you can call them.
On another thread someone else posted these UK sites:
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And these USA sites:
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You can also try Stanley Market and someone suggested tailor made work shirts which is a great idea.