I looked up your available digital channels at antennaweb.org. 3 of them should be easy to get from your attic with a medium directional antenna w/o a pre-amp. The 4th, ABC, is going to be a bear from your attic.
Since the channels are all higher UHF numbers, you may do well with a good Yagi style antenna from CM or Winegard. Try it first w/o a pre-amp. If you still can't get ABC, try a CM 7775 pre-amp and see if that works. The rule-of-thumb is that you lose about half of your available signal with an antenna in the attic, so up the antennaweb.org recommendations by one or two increments to select the right level of antenna.
Your channel azimuth grouping is pretty tight. Spread is usually not a problem under 30 degrees with a bay/bowtie antenna or 45 degrees with a Yagi, YMMV. Aim the antenna at your weakest channel and adjust from there.
A final note, many forum folks are very high on the CM4228 8-bay antenna; however, you should be aware of its large size (as delivered) and heavy weight. For an attic installation, getting one through the typical attic hatch my be very difficult, if not impossible. Also, depending on where you suspend it in the attic, the weight could have structural weakening implications. Fore warned is fore armed!