Your post has been up for a day or so without any responses. I cannot comment on the circuit you present without building it myself. I would suggest you try the same and see what happens.
I can add some general advice:
1) IR detection based on simply having an IRED and detector is very susceptible to noise and false signals. I would suggest that you follow the common practice of using a modulated IRED and suitable demodulation for detection . For example, the IRED can be modulated at 38 KHz, which is then sub-modulated at around 1 KHz. Packaged units are available to do the decoding. Units by Sharp and Sony are readily available in the USA at surplus dealers. I have used the Vishay TSOP321XX with good success, and the new units are not much more expensive than the older, surplus units. The TSOP is about the size of a TO-92 transistor.
2) Perform a search on this forum using the term: line follower. There are numerous other threads on the same subject.
3) The following site has good suggestions and sample code for the 12F5XX or 12C series of PICs for IR detection and obstruction avoidance:
http://users.frii.com/dlc/robotics/projects/botproj.htm
4) Last, depending on how much work and innovation you want to do and how much time you have, I recommend you visit this site:
http://www.navfltsm.addr.com/ndb-nav-history.htm
The “four-course radio range” was used for aircraft navigation until the mid-1950's. One could make an analogy between that method and a line follower. For example, the left IRED could transmit one code, and the right IRED could transmit another code. When exactly on the line, the codes would mix, and hypothetically, an error signal proportional to the deviation from the line could be calculated. The biggest problem I can see at the outset would be to get a line that reflected IR a lot better than the background. Since I have never tried any such thing, I have no suggestions to give you, but it seems to me that any line follower based on IR will have to solve that same problem to some extent.
Good luck. John