For trajectory data look at:
ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/russian_msu/vega-1/a1_coord.trj ,
and for additional data description:
ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/russian_msu/
Note: 
VEGA-2 (no source; a very similar trajectory of VEGA-1 may be used);