David,
Has Herceptin already been used? If not it will be easier to obtain since it is an approved drug. Also it may be more suitable initially than Lapatinib for advanced liver cancer since it is given intravenously instead of orally for Lapatinib.
Many members of the forum have had fast success in reducing liver metastases with Herceptin.
Concerning compassionate access to Lapatinib see the info supplied by Joe (or contact him) on this web site:
http://her2support.org/vbulletin/showthread.php?t=24042