I have three suggestions:
- Run our Premiere Pro Bench Mark PPBM5 so we can see what your system is and how well it performs.
- Investigate upgrading your system to at least quad core (you did not specify your CPU model number or the computer vendor/motherboard so we cannot be more specific with recommendations
- Tune your system to get rid of processes that are not necessary.
Without details, nothing more can be said than Bill already did.
What is your source material, HDV, P2, AVCHD, XDCAM, RED, EPIC. or something else? How long is your time-line? AFAIK there does not exist an i7 dual core. What are your sequence settings and what are your export settings? Any third party effects added? Any third party hardware in use? etc.
Just for your information I have seen very few (if any) encoding operations that do not encode much faster than realtime. I have AVCHD 1920 x 1080 material and typically encode both to MPEG2-DVD and H.264 Blu-ray. I do not use any AE and very few effects, typically only MPE GPU accelerated color correction.