Mike H:
Since you will be voluntarily releasing with ten or more but less than twenty years enrolled you will receive 3.5 days of pay per year of calculated service. If it's 20 years or over enrolled you would receive 7 days per year. (All this information is in CBI 204.54 - see http://www.forces.gc.ca/dgcb/cbi/engraph/home_e.asp?sidesection=6&Section=204.54&sidecat=21&Chapter=204#204.54)
You joined in April 1996. Assuming you have no NES, ED&T, LWOP or time in the Supp Res since then, you will have between 10 and 12 years of calculated service - that's every day from enrollment through 28 Feb 2007 inclusive, plus all class B and C time from 01 March 2007 onwards, plus all paid class A days from 01 March 07 onwards multiplied by 1.4. Not knowing your planned release date, I can't be more precise
Or, in mathematical notation: ( (All days enrolled prior to 01 March 2007 not NES, LWOP or ED&T) + (All days class B or class C from 01 March 2007 onwards) + (All paid days class A from 01 March onwards)*1.4) / 365 , rounded down.
Let's assume it's 11 years calculated time. You would receive 3.5 days per year, multiplied the 11 years calculated above, for a total of 38.5 days of pay as your RFRG.
From your profile, you are a Cpl - I'll assume you are at maximum IPC. Right now that's $125.86 per day. Therefore, your gross RFRG would be $4845.61 ($125.86 per day x 38.5 days). You can elect to have it rolled directly into an RRSP, in which case no taxes will be withheld. If you decide to take it as cash, taxes will be withheld - I think the basic calculation is 20%, but I won't swear to it. If 20% is withheld at source, you'd receive a payment of $3876.49.
There is also the pension plan. You are now contributing to it. You can also choose to have all your service prior to 01 March 2007 counted for pension purposes - that's the "election" you've received paperwork about. If you want to count all your service prior to 01 March 07, you will have to pay back what would have been taken off your paycheque had the pension been in place, plus interest. (it's a little more complex than that, but that's the basics). You can pay that money back in a lump sum, in monthly installments, or in a mix of both. You can also choose to buy back only a portion of that service.
As Rifleman62 stated, there are different options for the pension once you release (assuming it is not a medical release). The decision whether to elect to buy back or not, and if so, how much to buy back, is different for every person; current finances, marital status and when you served part-time and full-time all factor into the decision. While people on an internet message board can provide some information, it's ultimately up to you to research the situation and make a decision you are comfortable with.