Wu-Ki Tung, Group theory in physics, Counter Reserve 530.15 M52, S-LEN 530.15 Mh2;1&2. This book is very useful for the representation theory covered in the first part of the first term.
J.F. Cornwell, Group theory in physics, Vol 1 530.15 M44 and Vol 2 530.15 M44.2. Very complete book covering the classification of the Lie algebras, sometimes hard to follow.
J.F. Cornwell, Group theory in physics: an introduction, 530.15 N76, S-LEN 530.15 N76;1&2. An introductary version of the above, very useful.
R. Carter, G. Segal and I. MacDonald, Lectures on Lie groups and Lie algebras, Cambridge UP, Cambridge, 1995. A nice book which includes a decription of the homeomorphism between SU(2) and SO(3).
C. Nash and S. Sen, Topology and geometry for physicists, 514 M3, the original and still the best, by our own Nash and Sen. Out of print and can be hard to get. Good for the second half of the course.
M. Nakahara, Geometry, topology and physics, 530.15 N0 and the new edition at 530.15 N0*1. Very similar to Nash and Sen but leaves out exact sequences (!), easier to get.
A. Hatcher, Algebraic topology, http://www.math.cornell.edu/%7Ehatcher/AT/ATpage.html Very complete, nice book, formidable.