Calculus: Micheal Spivak's Calculus(the definitive theoretical presentation of calculus),Donald Estep's Practical Analysis In One Variable,and Gilbert Strang's Calculus (the latter 2 for applications). Strang is available online for free.
Algebra/Linear Algebra: A Course In Algebra by E.B. Vinberg (gives an integrated introduction to both linear and abstract algebra with lots of applications,especially to geometry:VERY readable and reaches a very high level of coverage by the end), Michael Artin's Algebra (more intense,but similar in spirit,a second edition coming out later this year,can't wait for it)
Category Theory: Category Theory by Steven Awodey(the definitive introduction for beginners-I wouldn't recommend anything else for a beginner)
Topology: A First Course In Topology:Continuity And Dimension by John McCleary (the best introduction to the subject)
Overview of Mathematics: Mathematics:It's Content,Methods And Meaning by A.N.Kolomogrov,etc. (The great classic by 3 Russian masters of mathematics,will give you the best bird's eye view of the subject)
That should get you started and give you the tools needed to go forward. Good Luck and welcome to the sorcerer's guild!
