I would suggest a Krieger 1:8 twist 26" Remington Varmint Contour. It should fit your existing stock and will be great for bullets up to 80 grains.
Replacing the barrel should be the "crown jewel" in a makeover that includes action accurization, bedding, and trigger adjustment/replacement. Competent gunsmiths like Guntech can turn your rifle into a hummer.