There seems to be a misconception on this site that Captain America isn't making as much money as Thor and while that may be true the numbers aren't staggeringly different. Here are the weekend Grosses for the first 3 weeks of Thor and Captain America.
Thor
Weekend Gross - Week 1 $65,723,338 Week 2 34,703,035 Week 3 $15,455,304
Theater Avg. - Week 1 $16,618 Week 2 $8,757 Week 3 $3,939
Gross-to-Date in first 3 Weeks $145,361,459
Captain America
Weekend Gross - Week 1 $$65,058,524 Week 2 $25,554,303 Week 3 $13,021,922
Theater Avg. - Week 1 $17,512 Week 2 $6,879 Week 3 $3,597
Gross-to-Date in first 3 Weeks $143,203,967
As you can see the numbers are very comparable, the budget for Captain America is $140,000,000 and the budget for Thor is $150,000,000. Given the $10,000,000 difference in budget, the Average Theater count, combined with the competition of Harry Potter the week before and 3 high profile release the week after you can actually say that Cap is doing better than Thor domestically.
Thor
Domestic Gross $180,825,651
Foreign Gross $267,166,560
Worldwide Gross $447,992,211
Captain America
Domestic Gross $143,203,967
Foreign Gross $103,000,000
Worldwide Gross $246,203,967
Internationally Thor has made $267,166,560 which is about 60% of its gross and while it is expected that Cap won’t do as well as Thor internationally, Cap is still in his 2nd week of an international run that is still early and has made $103,000,000. It's still needs to be released in Denmark, India, Norway, Sweden , Belgium, France, Germany, Finland, Greece, United Arab Emirate, Turkey, and Japan.
If you look at the numbers they compare pretty well to Thor and since Thor's sequel has been green lit you can pretty much guarantee Cap will too. With the Avengers coming out next year it's pretty much a guarantee that more of the general public will know more and want to see more from Thor and Captain America.