Ouch! I would contact the eBay seller to get a replacement battery as this one is clearly bad. The blinking LED's is telling you the battery is bad. From the MacBook Pro User Guide:
[quote]***If you press the battery button, and all battery indicator lights flash five times quickly***
Your battery needs to be replaced. Contact an Apple Retail Store or an Apple Authorized Service Provider.
***If you press the battery button, and the battery indicator lights flash from left to right and then from right to left, five times in a row[br]
***Your battery is not recognized. Contact an Apple Retail Store or an Apple Authorized Service Provider.[/quote]