So much of this depends on the context. From the mention of OpenOffice I assume that this is a one-off hand-assembled document rather than programmatic ouput from a DB or whatever. I've only had an occasional use for that and I've always found a suitable web-based generator to paste in from, e.g.That seems to be among the better online options in that it has a wide choice of formats and the option of EPS output - I'm not overly inclined to trust low res bitmaps for something like this.
Formatted printed output from programs generally means Postscript in any event (for a Unix shop at least ;-) ), so inserting a barcode generation function in the header and then calling it with the right options later is no big hassle. I wrote a Postscript EAN-13 generator a few years back - it only took about an hour and I'm far from a Postscript expert, but I notice the same author as above has a far more comprehensive library atwhich looks promising, although I have no direct experience of it.