I currently have a Dlink DIR-655, but it's single band. I'm thinking of upgrading it to DIR-825 for a stable dual band router.
As far as your current router goes, I would advise that you look into DD-WRT to see if it's compatible with your Linksys. Linksys tends to make decent hardware, but absolutely terrible firmware. DD-WRT will make it much more stable and give you a bunch of new features without having to pay a dime.
I have the DIR-655, and I like it, but I didn't realize it was single band until after I bought it.
The DIR-825 sounds good, but it gets bad reviews on Newegg for some reason.