If you can shop online in Chinese, it seems you can get it here…
https://shopee.tw/（YN-27）Monin-杏仁風味糖漿-i.164304339.3329895623
Actually, I recognize the seller, Mixology Studio. They are right at Wanfang Community MRT station. You can go to their place and physically buy stuff if you are unable to manage online. Best to call ahead and check they have it in stock though (02)2230-0246.
thanks!