I assume you mean you want a quote to the right of the image you currently have as your sig, AND the quote already there, underneath all this. If this is correct then you have 171 characters to work with...
its very hard to explain.....you must have the quote that you want next to the image continuous to the image URL, eg:
[ing]http://www.tky.3web.ne.jp/~pennywiz/foursymbols.gif[/ing]new quote new quotenew quote new quotenew quote new quotenew quote new quote
"Whilst I may not agree with your opinion, I'll defend to the death, your right to express it."
Having you new quote as continuous text with your image URL will put it to the right hand side when you view it.....leaving a gap will put it underneath.