The president, no matter who he is, has relatively little power over the economy, and what power he does have typically takes YEARS to come to fruition, both for good and for bad. The benefits of Bush I's domestic policies, for example, contributed a great deal to the "Clinton" prosperity of the '90s, which really came into being a couple of years after he was voted out of office. Conversely, Bush II's domestic policies largely contributed to an economic crash that didn't hit until the waning days of his 8 year presidency. Even if Romney were elected, you're going to get at least two to four more years of whatever track the economy is currently on at this moment (which, by the way, has seen continued growth and job creation for years now, it just had a really really shitty starting point).
Rather than feel like you're voting for or against an economy, it would be wiser to look more at how the two candidates come to their proposed policies and evaluate the merits (or lack thereof) of their plans and characters.