Hello bdur,
Yea, you can get assistantship or fellowship to do your masters in US if you have guts to get good score in GRE. I have observed that many nepali are afraid of GRE (they prefer to escape GRE) and end up with some 4th tier or non-ranked universities where it's very hard to get some sort of financial assistance.
You don't have enough time to apply for fall 2007 term (deadlines are almost over). So, you have enough time to prepare for TOEFL and GRE (you need to get good score in both) and apply for spring 2008 or fall 2008. Just to let you know GPA, recommendation letters and test scores play vital role in admission decision along with financial assistance.
Good luck with your application !!