From the many articles in old newspapers, it appears that one of the one of the victims, Mr Cook, died at the Talbot Arms Hotel, not the Talbot Inn where the Williss family were. Whether or not he was poisoned there, I can't tell. It seems he poisoned many people in various public houses.
However, the murders did destroy the Williss' business. In 1855, two bodies were exhumed for an inquest, and as the Talbot Inn was close to the church graveyard where they were buried, so the coroner had the bodies sent there, thinking that there were a great many outbuildings they could use. However, the bodies were sent into the Inn itself.
John Williss ran an ad in the Staffordshire Sentinel and Commercial & General Advertiser in Jan and Feb (maybe longer) stating :
John Williss, Landlord of the Talbot Inn, Rugeley, in this County respectfully informs his friends and the public in general, that, since the performance of the surgical operatio s chich recently took place there, such thorough and effectual painting, papering, cleansing, ventilation, and other means of purification have been adopted, and no offensive trace thereof can possibly remain etc etc. The rest of the article is naming inspectors that expressed satisfaction. The letter was dated Rugeley, 10th January, 1856.
Digging in much newer papers, in 1995 a newspaper (Lichfield Mercury) ran a historical look at "Old Rugeley" in parts over a few weeks, taken from a publication written back in the time, and it appears that the Talbot Arms Hotel became the Shrewsbury Arms, and is now (in 1995) the Shrew Kafe Bar. They also state the Talbot Inn business failed because people wouldn't go back. The description might help you place it:
Soon after you leave the railway station and have crossed the bridge by the flour mill, and left Mrs Palmer's house and the two churches in the background, you come to the Talbot Inn, now a noted building and almost ruined from the circumstances of the bodies of Mrs William and Walter Palmer having been opened there. The poor landlord is dreadfully distressed at having lost his business and passes the day with his hands in his pockets, roaming about the large stable yard at the back of the house, or to relating to the one or two friends, who still drink their ale with him, the history of his misfortunes.
There are ads in 1856 where John Williss is selling off livestock and farming implements, and then in Staffordshire Advertiser 14 March 1857 there is an ad for an auction for the sale of ale barrels, brewing and dairy utensils, household furniture and other effects belonging to Mr John Williss, "who is leaving".
Hope that helps!
PS During the inquest, one of the barmaids at the Talbot Inn was questioned as she claimed to have seen William Palmer bring a drink of some sort to a different victim (Mrs. Mills?) at the Talbot Inn, but as the inquest was on Ann and Walter Palmer, it didn't appear to be followed up on (at least at this inquest).
I highly recommend you go to a library with free access to the old newspapers, as there a lot on the Williss family besides the murder bit, such as wedding notices etc.