Elements and Ephemeris for C/2012 S1 (ISON), grabbed on 2013/10/21 from MPEC:


These people always seem to have latest link:
http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=CK12S010


Source: 
http://www.minorplanetcenter.net/mpec/K13/K13U17.html

    C/2012 S1 (ISON)
Epoch 2013 Nov. 4.0 TT = JDT 2456600.5
T 2013 Nov. 28.77441 TT                                 MPC
q   0.0124442            (2000.0)            P               Q
z  -0.0001662      Peri.  345.56446     +0.31513553     +0.51237362
 +/-0.0000005      Node   295.65277     -0.75893582     -0.36934579
e   1.0000021      Incl.   62.39956     -0.56982981     +0.77527864
From 4789 observations 2011 Sept. 30-2013 Oct. 21, mean residual 0".5.


;;IDL
tperi=anytim('2013/11/28')+86400.*.77441 - 66.184 & q=0.0124442 & O=295.65277 & i=62.39956 & w=345.56446 & e=1
;;OR:
;elements={tperi_ET_ccsds:anytim(anytim('2013/11/28')+86400.*.77441,/CCSDS),q:0.0124442,e:1.0000021,O:295.65277,i:62.39956,w:345.56446}