A Biologist's guide to mathematical modeling in evolution and ecology (Otto) is a very good book that is presented for people that have highschool level in mathematics (It makes a good review in linear algebra for example). It is highly accessible and in the meantime it goes pretty far as it ends up talking about the application of diffusion equation in population genetics (Kimura). This book presents some important models in population genetics but as it aims to provide the tools for mathematical modeling in ecology and evolution it may under-considerate some fields of ecology and evolutionary biology. The book does not talk about population structure nor about evolutionary game theory (I think) for example.
There are several books that offer an introduction to population genetics. I read Principles of Population Genetics (Hartl & Clarke). I appreciated it but if I were you I think I would rather try Elements of population genetics (Charlesworth) or Population Genetics (Hamilton). There is also Genetics of Populations (Hedrick) but I guess (I might be wrong) that it is too much empirical population genetics and not enough of theoretical and mathematical population genetics. Finally, there's a book called Mathematical population genetics (Ewens). I am currently reading it. It is a good book but it is not an introductory book and it doesn't cover much of the most common fields in population genetics.
If you are particularly interested in age-structured population, Evolution in age-structured populations (Charlesworth) is a very good book. Coalescent theory offers a very interesting set of mathematical tools in evolutionary biology.
Coalescent Theory: an Introduction (John Wakeley) is a good book. I haven't read it completely for both time issues and because it is fairly complicated!
Modeling evolution (Roff) offers some discussion on how to mathematically define fitness from phenotypic traits. While it is interesting I would not counsel you to buy it. Moreover, all the mathematics are quite basic and it aims to explain how to perform mathematical modeling with R which is to my opinion kind of stupid, a software like Mathematica does a much better job for constructing and analyzing math models.
Evolutionary Conservation Biology (Ferrière, Couvet and Dieckmann) is a very good book of theoretical conservation. It develop some mathematical models that are of special interest to conservation of populations and communities.
So in short, I'd recommend Sally Otto's book if you want to ensure your knowledge in mathematics. Then, you should try one of the book I suggested in the second paragraph (except maybe Ewens's book) but as I know only one of them, you might want to wait other answers to get different opinions.
Hope that helped!