You have at least two ways:
If your format is not too exotic (like the case), you can use the advanced separator parameters of tFileInputDelimited. You'll find it as the first advanced parameter. When you activate it, you'll be able to set the separator for thousands and for decimals. As you may see, the default is '.' for decimals and ',' for thousands.
If your format is very weird, then read the number field as String and convert it to a Double in a tMap in a pure java solution like this.