You'd win your bet. You can find a detailed breakdown of the polling numbers on my profile page; here are the relevant ones for Catholics of all stripes:
55% McCain, 43% Obama - Weekly mass-attending Catholics 6,9
52% McCain, 47% Obama - White "regular-mass-attending" Catholics12
51% McCain, 49% Obama - White Catholics1,7,11
45% McCain, 54% Obama - Catholics1,4,6,8,9,10,11,12
37% McCain, 61% Obama - Non-weekly-mass-attending Catholics6,12
xx% McCain, 67% Obama - Hispanic Catholics8,11**,***, ****
** No source provided voting percentages for the other party.
*** Associated Press (citation #11) reports this number as 72%, instead of the 67% other media gave it.
**** Note that some media are reporting the same numbers for the Hispanic and Black vote in general, as well as for those same groups with Catholic or Protestant affiliation.
Citations:
1 The Awesome Blue God -- How Obama Forged A New Faith Coalition
2 Exit polls: 78% of Jews voted for Obama
3 Utah's red loses some of its luster
4 Obama's Religious Appeal: Still Missing Evangelicals - which TIME renamed as Obama: Bringing (Some) Evangelicals In
5 The Evangelical Electoral Map
6 What's wrong with Catholic voters? What's wrong with Catholics?
7 Evangelical Voters Favor McCain by Wide Margins
8 Catholic voters heavily favored Obama, analysis shows
9 What Happened to the Catholic Vote?
10 Loyal to the End: Evangelicals Stay the Course
11 Obama results show gains in key religious voters
12 How the faithful voted
13 Exit polls: How Obama won
All numbers cited above are the earliest ones reported in the press. In cases of multiple reports, some percentages cited were not exact. However, the numbers above are within 2% of all sources cited, lending credence to the general number & placement overall.
The amount of lies told in the Spanish-language and Kreyol-language media about Obama's abortion stance were criminal.
And almost no Catholic bishops in the US speak either language fluently enough to make an impact in those quarters.