If Jo makes it through qualifying she has the choice of:-
Roberta Vinci (ITA) 20 (CH=11 Jun 2013)
Anastasia Pavlyuchenkova (RUS) 25 (CH=13 JUL 2011)
Alisa Kleybanova (RUS) 101 (CH=20 FEB 2011, She hardly played at all in 2012 and is only now beginning to get back in form.)
Svetlana Kuznetsova (RUS) 29 (CH=2 Sep 2007)
All of them would be a challenge but Kleybanova probably presents the best chance of a R1 win.
It's not much of a consolation but Jo won more games than Siegemund and Pironkova did against the Italian. Also 18 points won is the same as QFs of a 50k+H... Still it's a shame she couldn't win that one and make the main draw