I strongly suggest you read my thread, Page 3 and Page 4 discuss the "Large dollar" type issued between 1967 and 1990.
http://goccf.com/t/380477&whichpage=3(Scroll down a few posts and each of these coins is discussed in some detail)But if you are pushed for time.
The coins were crown sized (38mm) and issued between 1967 and 1990 every year except 1968. The coins were sold in two grades - Standard Uncirculated which came in a plastic case and Proof which came in a ring style box. The former were always cupronickel, the latter were polished cupronickel, although they became silver in 1977, except for a silver 1974 games dollar.
The uncirculated versions were cheap and only cost a few dollars and even today with the exception of one coin (1970 Cook islands dollar), can be picked up very cheaply. The 1967, 1969 and 1974 Games dollar all had mintages of over 200,000 and have no value above face. The others will cost you around $3 - $5 (1970s) and about $5 - $10 (1980s).
The Polished coins are also not worth much until they become silver and even then, they are worth barely melt value, which is around $25 - $40 as they are 92.5% silver. These are beautiful coins when polished and the 1980s bird coins are more stunning!
In 1989, 4 x $1 coins were issued for the Commonwealth games and in 1990, one further $1 large coin was issued as part of the 1990 150 years set.
These large coins were legal tender, but given they cost over face value and had very limited numbers (Most years about 10 - 25 thousand) it was not worthwhile spending them and many shopkeepers probably would not have accepted them.
The small sized dollar was introduced in early 1991, despite being dated 1990. Starting that year the old Dollar coins became $5 coins and have remained so since.
The different effigy the OP mentions was used on 1979 - 1982 dollars and was designed by James Berry (1906 - 1979), this shows the Queen wearing a Tiara.