Making Python Add-In using tools built in ModelBuilder?

I have made a set of tools in a toolbox using ArcGIS 10.2 using the model builder.

I would like to distribute them as a tool bar, and so created a ArcGIS Python Add-In I was hoping that I could export the tools as python scripts and copy the code into the Add-In. However, it does not seem to be as simple as that.

Is it possible with Python Add-Ins to make a window for entering in parameters and run a script in the way tools/toolboxes work?

Update

I found a useful blog post.

This is my code

import arcpy
import pythonaddins
import os.path

class multiplebenefits(object):
    """Implementation for ArcGISAddin_addin.multiplebenefits (Tool)"""
    def __init__(self):
        self.enabled = True
        self.checked = False

    def onClick(self):
       # name of toolbox without tbx extension
       toolboxName = "mytoolbox"
       # name of tool to be executed
       toolName = "mymodel"
       # create string with path to toolbox
       toolboxPath = os.path.join(os.path.dirname(__file__), toolboxName + ".tbx")
       # call geoprocessing tool
       pythonaddins.GPToolDialog(toolboxPath, toolName)

But I get an error message:

Failed to open tool mymodel (mytoolbox.tbx)

TypeError: GPToolDialog() takes at most 1 argument (2 given)