Wenger has been urged to add to his squad after his side's stuttering start to the season.
But he has been determined to maintain stability in his squad by keeping players such as Walcott, who is out of contract at the end of the season.
Wenger explained: "We have now got Tomas Rosicky and Abou Diaby fit again. We have got a complete squad. We are still looking in the transfer market but will not go for average players."
Expanding on Walcott's situation, he added: "We are on a good road but in this situation as long as nothing is signed, you are cautious, but I am optimistic we will get to a happy conclusion.
"I was optimistic last week, but I am a bit more optimistic this week. I expect him to sign [by the end of January]."