Sounds like you need a dahon androes stem extender. I have one spare but I am not letting it go as they are rare. I suggest you do a search on ebay world wide. I paided about 55 pounds for mine. Has tbe advantage of being quick release. You need about 9 cms flat section on the bars 25.4 mm
Extends reach by around 9 cm

Another possibility is fitting a qr to a adjustable ahead stem which go up to 130 or more.