You could try increasing the maximum heap size for the Ant process. In Ant 1.6 I believe you add it to (or set) the environment variable ANT_OPTS. Check the JDK tools documentation for the switch: -mX$$$ IIRC.
As I said the memory of computer is 1GB, it should not be the problem.
As far as I know, Java won't use more than 64MB per default, independently of how RAM you actually have. If you want it to use more, you need to tell it via the -X... switches.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus