Hadrian held COS III from 119AD to his death in 137AD - 128AD is about right for this coin (maybe as late a 132AD).
I think its Minerva on the reverse holding a spear and leaning on a shield.
Hadrian coins are popular and therefore usually attract good prices, he was a decent emperor, has been remembered well and due to the walls he built (and their remains) all over the Empire he is prob one of the widest known Emperors today.
As always prices vary between Dealers and
ebay - I found a similar one on Forum Ancient Coins for about £200GBP - It should be noted though that it was in slightly better condition and as Bacchus2 has said the silver on yours is not as well preserved as most.
I like the way yours looks - its nice. I could see it selling in an auction for £50, maybe a bit more if you get a bidding war. Poor quality Hadrian bronzes often fetch £20.
If you can find the RIC number for it it could indicate if its rarer than the norm and maybe inflate the price.