I would tend to agree with Soix that a pre amp processor might be a better place to look for upgrading. However, if you are still on the hunt for a better amp. Have a look at this Llano A-200 that's on Audiogon.
http://app.audiogon.com/listings/solid-state-llano-design-a-200-2012-12-19-amplifiers-87571
reviews:
http://www.audioreview.com/cat/amplification/amplifiers/llano-design-group/a-200/prd_116310_1583crx.aspx
http://app.audiogon.com/listings/solid-state-llano-design-a-200-2012-12-19-amplifiers-87571
reviews:
http://www.audioreview.com/cat/amplification/amplifiers/llano-design-group/a-200/prd_116310_1583crx.aspx