searchable text chart format

The following script creates a chart in pdf format. All the text on the chart is searchable. I need to create a chart which will be put in a MS Word 2007 document (as part of a much larger document) and then converted to a Pdf. Which format should my chart be and which backend should I use? Thus far, I have been using Agg and putting in pngs...the quality is great but they are not searchable! Thanks.

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import matplotlib as ML
ML.use('Pdf')
import pylab as PL

fig = PL.figure()
ax1 = fig.add_subplot(111)

lstX = range(1,100)
lstY = map(lambda x:PL.sin(x/PL.pi),lstX)
ax1.plot(lstX, lstY, color=(0.87,0.0,0.0), lw=2, alpha=0.6)
ax1.set_ylabel('control of line styles, font properties, axes properties')
ax1.set_xlabel('trys to make easy things easy and hard things')

ax1.set_title('python 2D plotting library which produces', weight='bold', size='large')
fig.savefig('out', dpi=72)