then if you're just doing normal work you should be fine, its a low end power supply when you use it heavily like 4+ hours a day, if you don't use it that much and you don't game heavily on it you should be fine.
80 Plus (trademarked 80 PLUS) is a voluntary certification program intended to promote efficient energy use in computer power supply units (PSUs). Launched in 2004 by Ecos Consulting, it certifies products that have more than 80% energy efficiency at 20%, 50% and 100% of rated load, and a power factor of 0.9 or greater at 100% load. Such PSUs waste 20% or less electric energy as heat at the specified load levels, reducing electricity use and bills compared to less efficient PSUs.
it just means that the power they supply is more than 80% of what it states on the box and bronze means that it can bit very close to this level fairly easily.