So, taking the $6500 from the IRA would save you, what, about $450 since you'd have it paid off in a year anyway? A bit less since you'd have been making regular payments on the loan.
Also, you can't "replace" it unless you get it back in by April 15th. After that, it counts towards your contribution for 2014.
How are you coming up with the 5.45% number? You didn't contribute all the money in 2005. So while the total may have increased that much since then, some of it must be going up at a higher rate.
Personally, it seems like too much work for not enough benefit, but I don't know your whole financial picture. Like, could you cut anything else from your budget? Also, you didn't ask, but I would look into your investments and investment behavior a bit. While I agree it's hard to beat 6.8%, there are other factors. Are you in a high-paying profession now? Or do you expect to hit income levels past those which allow Roth contributions? Are you making regular contributions or trying to time the market? I feel like people who were making regular contributions from 2005 til the present would be doing better than 5.45%