Well, you could try to copy the nodes and edges with the labels you want into a new editor tab and then save that sub-graph in TGF format. TGF is a very simple text-based format which you might be able to modify by hand so you can import the texts into another application. This apporach will only work for nodes/edges with at most one label, though.
A more complex approach would be to use XSLT to extract label text from GraphML.
