|Software - Editing UPDATE|
You can get many types of software for editing, including many software packages which now routinely come with a new computer. Apple's iMovie is a surprisingly good little editing package - and just might suit your needs.
Remember: Software and hardware comes down every year. Moore's Law (a famous computer axiom) says that every 18 months computer power doubles while the price comes down by half. So buy what you need.
Final Cut Pro
Adobe After Effects