Can I use sealer over recycled asphalt to retain it?
No. Sealer isn't nearly strong enough to support the tremendous tearing forces at play. 

Instead, watch your local community sale websites for used or leftover concrete pavers. You want the heavy duty ones, which are about 2-1/2" thick. With a little patience and luck you should find a relatively inexpensive lot that will give you proper pavement for life. You could even use the recycled asphalt concrete as a base, with a little sand over the top to make leveling easier.