The Random House dictionary would certainly work as a good reference.... As for a good book on just learning Japanese via romaji, I have no idea. I personally am studying Japanese using the Instant Immersion computer program and audio CDs (both of these are pretty good - several of the exercises in the program focus on romaji, and the audio cds can get you pretty close to a word, just check the dictionary for spelling). I'm also using a couple of books to help me learn Kanji, but these would be less useful to you I expect (they both give either the romaji or hiragana/katakana pronunciations though). However, none of these sources would necessarily help you learn what a person would say when angry, as they are primarily meant to teach you polite conversation.
So, my recommendation is that you watch anime, preferably one with lots of fighting. In most of those, the characters tend to get angry pretty frequently, and if you can at least get your ear trained so that you can transcribe what they say in romaji, you can look up what they said and figure out what parts of that your character might use. Just from what I remember of anime, kusa (or kusaa or kuza/kuzaa) is used pretty frequently (means something like damn-it - a generic frustrated utterance). Anyway, I hope that helps some, and good luck
[Edit:] Another option is to read untranslated manga of the same genre - that way you don't have to worry about whether you hear the words correctly. By the way, if you have a specific question on a word or phrase or something, I have two close friends who know Japanese - one fluently and the other pretty proficiently. So feel free to send your question in my direction via a PM or IM. Of course, they both learned by living in Japan, so I doubt seeking their help for a good book to learn from would be that useful
がんばろ - Ganbaro
. I'm on a one-year student exchange in Japan, in Yamanashi, a region just west of Tokyo. And therefore consider myself to be the best one to give you a suggestion about the books...
