Beta blockers can cause those side effects of cold hands and feet.
This is a common side effect. Do you take the propranolol at night? Try taking it in the morning, and see if there is any difference.

Propranolol is listed in the reference I use called Drug Induced Nutrient Depletions.
The nutrient that was studied was CoQ-10. Since low levels of CoQ-10 impact the heart, I'd suggest you start a good supplement of this. (buy quality, and gel cap form, not dry powder capsules). You will need at least 200mg a day or more. Whatever you can afford, as it can be costly.

Here is a link with some information for you:
http://www.swedish.org/16749.cfm

I realize you need some beta blockade for your heart, but use of these drugs is problematic in diabetics.
It is a tight place to be...IMO.
Their biggest downside is that they mask symptoms of low blood sugar. While doctors are targeting high sugars, new research shows that LOWS are very damaging.

You can try this: soak your hands in epsom salts before going to bed each night. (at least 1/2 hr in lukewarm water) The magnesium will soak in and open the blood vessels and improve the circulation. (magnesium dilates blood vessels). This will help, but also point to magnesium oral as being your goal.

It is possible you may improve your heart functions with the CoQ-10 and magnesium and be able to get off the beta blocker in the future. This is a MAYBE... but a goal that will improve your daily life.

Cardiac arrhythmias respond to restoration of magnesium in some cases.