You need to first naturalize and become a US citizen. Only US citizens can file I-130 for parents, and In-law cannot file for Inlaws, so NO US Citizen spouse cannot file for inlaws.
Just look at form I-130 directions page 1:
QUOTE
Who May File Form I-130?
1. If you are a U.S.citizen you must file a separate Form I-130 for each eligible relative. You may file a Form I-130 for:
A. Your husband or wife;
B. Your unmarried child under age 21;
C. Your unmarried son or daughter age 21 or older;
D. Your married son or daughter of any age;
E. Your brother(s) or sister(s) (you must be age 21 or older);
F. Your mother or father (you must be age 21 or older).
2. If you are a lawful permanent resident of United States, you may file this form for:
A. Your husband or wife;
B. Your unmarried child under age 21;
C. Your unmarried son or daughter age 21 or older.
Who May Not File This Form I-130?
8. A grandparent, grandchild, nephew, niece, uncle, aunt, cousin, or in-law.
http://www.uscis.gov/files/form/I-130instr.pdf