Hello, I need help deciding which is the best software development process for the project I'm involved in. I'll outline the project features.

The project consists in building an application for a device that reads payment cards and performs online payments.
The requirements are almost completely set (I have a 300 pp specification) and very stable. Only minor changes are expected.
The team is composed by... hmmm, let me think... ME! Only me. My boss is supposed to help me, but only from time to time.
It is a small project. I think that it should take me less than a year to finish it if I don't find major problems.
The language of choice is Java.

My company develops software without doing any analysis, design, etc. However, I wanted to do things the right way and follow a suitable process. But I want a lightweight process, since my project doesn't demand a full-fledged classic process. That's why I got interested in agile methods. But after browsing some XP sites, I found out that XP is intended for risky projects with unstable requirements, which is not my case.

So, can somebody advice me on the best process to follow? Should I try another agile process instead of XP? Or is XP fine for me anyway? Or should I forget about agile processes and try something different?

Thanks in advance