First, don't try to drive the car if the bushing has worked out. The steering won't work right. Second, you must pull the upper a-arm out to replace a bushing. Third, if you haven't done it before, I would not advise trying to do it yourself.
That said, if you can find a competent buddy it's not rocket science. But just be aware that suspension work can be dangerous because it involves the heavy weight of the car and suspension parts under great tension.
The real difference is this: If you can safely remove the arm at home with the help of your buddy, the price to repair could be small. $10 for the new bushing and maybe $20 for the machine shop to press it in. If you managed to keep track of the alignment shims that were in there you can just put them back where they were and avoid the cost of an alignment. Otherwise, you'll need a tow and the mechanic will charge $100 or $200 for the labor on top of parts, and require you to get an alignment for another $50-100. So you're probably looking at $30-50 versus $300-400.
But drop the car on yourself and $400 will look cheap if you're still alive. No joke there.
Plus, whether you do it yourself or not, if one bushing came out you probably need to take a look and think about an entire front end rebuild. There's a big factor here of where there's smoke there's fire. Not much sense in piecemealing it if you'll be back doing it again in the near future.
Good luck.