This is my first tab, but I think I got it for the most part. Becky varies 
fingerings throughout the song, but basically this is what it is-

Riff 1
E |---------------------------------------------|
B |---------------------------------------------|
F#|---------------------0------0------0---------|
D |-------0------0--------------------0---------|
A |--3-2-0--3-2-0--3-2-0--3-2-0--3-2-0----------|
D |---------------------------------------------|

Riff 2 -I think she uses a slide but you don't really need one.
E |---------------------------------------------|
B |---------------------------------------------|
F#|---------------------------------------------|
D |--12---10---12-12-12---12--10---/5--0--------|
A |--12---10---12-12-12---12--10---/5--0--------|
D |--12---10---12-12-12---12--10---/5--0--------|

E |---------------------------------------------|
B |---------------------------------------------|
F#|---------------------------------------------|
D |--12---10---12-12-12----15-15-15---17-17-17--|
A |--12---10---12-12-12----15-15-15---17-17-17--|
D |--12---10---12-12-12----15-15-15---17-17-17--|


E |---------------------------------------------|
B |---------------------------------------------|
F#|---------------------------------------------|
D |--12---10---12-12-12----12-12-12---10-10-10--|
A |--12---10---12-12-12----12-12-12---10-10-10--|
D |--12---10---12-12-12----12-12-12---10-10-10--|


E |---------------------------------------------|
B |---------------------------------------------|
F#|---------------------------------------------|
D |--5-3-/3-0----5-3-/3-0------/3-0-/3--/3-0-/3-|
A |--5-3-/3-0----5-3-/3-0------/3-0-/3--/3-0-/3-|
D |--5-3-/3-0----5-3-/3-0------/3-0-/3--/3-0-/3-|

Pretty much that. You'll have to make up variations or whatever. Hoped this helped though.