Getting attribute from CDATA-formatted XML

I have an XML with a node formatted as follows:
<headline2 width=“500”><![CDATA[<spane class=‘Headline’><span class=‘LinkTo’><a href="/us/success/collateral.aspx">your collateral<br /><span class=‘HeadlineSmall’>get info about it here</span></a></span></span>]]>

How would I retrieve the URL contained in the a href attribute? I have tried a number of ways: @a, @ahref, @href, as well as CDATA.@a, CDATA.@ahref, CDATA.@href and am stumped.