This is really a comment to Martin H, however, I don't have enough reputation to produce a comment at this time.
I followed your link to get textext, scrolled down to the Windows section of the installation heading. From there I followed the instructions to download and install 2. pstoedit and 3. ghostscript [I already run MikTeX (instruction number 1 on the list) through TeXMaker] I then downloaded and installed the 4. Textext. All of these installations were automatically performed in the usual way of downloading .exe files and clicking "next, next, ..., finish" through the dialog boxes.
At this point, following the advice given (by Martin H), I was unsure what was meant in his answer by "I placed the extension files in the ~/.config/inkscape/extensions folder"
Opening Inkscape at this time gives me the TeX Text option under the Extensions menu. However, clicking this yields the same error as encountered by Martin H. Following the link for the blog post provided and then the steps to fix this error, I open Inkscape only to get the error:
Traceback (most recent call last):
File "textext.py", line 936, in <module>
File "C:\Program Files (x86)\Inkscape\share\extensions\inkex.py", line 215, in affect
File "textext.py", line 349, in effect
RuntimeError: No Latex -> SVG converter available:
Pdf2Svg: Command pdf2svg failed: [Error 2] The system cannot find the file specified;
PstoeditPlotSvg: Command pstoedit -help failed: [Error 2] The system cannot find the file specified;
SkConvert: Command pstoedit failed: [Error 2] The system cannot find the file specified