Python script to grep fields and use values from file 1 as argument for another command

Hi Experts,
I am working one one python script in version 3.x and 2.6. Need your support to complete it
Basically for both commands i have telnet to device and run command and then receiving input File 1 and File 2
I have two commands, need to grep data and output in csv file.
Next script/code where want to use values from third column "inst"(Input file 1) and have to pass in other command as below and grep string and output in another file

Input File1 :

cpu facility      inst  used  allc   used  alloc used allc  used  allc 
1/0 sessmgr       5025 0.23%   50% 98.90M 230.0M   31  500    --    -- 
1/0 sessmgr          9   31%  100% 639.1M 900.0M   41  500  3588 12000
1/0 sessmgr         38   30%  100% 538.3M 900.0M   37  500  3580 12000
1/0 sessmgr         52   29%  100% 533.7M 900.0M   37  500  3592 12000
1/0 sessmgr         75   28%  100% 548.5M 900.0M   35  500  3587 12000 
1/0 sessmgr         91   29%  100% 539.1M 900.0M   35  500  3578 12000 
1/0 sessmgr        102   27%  100% 544.1M 900.0M   36  500  3580 12000 
1/0 sessmgr        129   30%  100% 545.1M 900.0M   35  500  3585 12000 
1/0 sessmgr        150   27%  100% 542.8M 900.0M   34  500  3573 12000 
1/0 sessmgr        172   32%  100% 540.3M 900.0M   33  500  3580 12000 
1/0 sessmgr        177   27%  100% 541.9M 900.0M   32  500  3583 12000 
1/0 sessmgr        196   29%  100% 535.8M 900.0M   32  500  3575 12000 
1/0 sessmgr        279   29%  100% 548.3M 900.0M   33  500  3593 12000 
1/0 sessmgr        285   30%  100% 539.5M 900.0M   33  500  3585 12000 
1/0 sessmgr        294   31%  100% 541.9M 900.0M   32  500  3589 12000 
1/0 sessmgr        302   34%  100% 536.7M 900.0M   35  500  3598 12000 
1/0 sessmgr        325   31%  100% 535.9M 900.0M   36  500  3582 12000
1/0 sessmgr        327   31%  100% 538.8M 900.0M   36  500  3580 12000
1/0 sessmgr        364   31%  100% 539.9M 900.0M   38  500  3599 12000

Now, want to use values from third column inst and have to pass in other command as below

This above command will give me output as shown in below Input File 2.
here only pasting one output from above command, similary other two commands will give similar output.

and have to keep only line "ave rate from user(bps)" as column heading(uplink througput) and "17104773" as its value in row and similarly "ave rate to user(bps)" in another column with heading(Downlink throughput) and "247272821" its value in row in another CSV FILE.

Input File 2:

Thursday July 11 17:10:45 IST 
 
Total Subscribers       : 2978
Active                  : 2978          Dormant                 : 0
peak rate from user(bps): n/a*          peak rate to user(bps)  : n/a*
ave rate from user(bps) : 17104773      ave rate to user(bps)   : 247272821
sust rate from user(bps): 16999794      sust rate to user(bps)  : 246777077
peak rate from user(pps): n/a*          peak rate to user(pps)  : n/a*
ave rate from user(pps) : 13117         ave rate to user(pps)   : 27879
sust rate from user(pps): 13233         sust rate to user(pps)  : 27976

Expected output from Input file 2 in csv file:

sessmgr instance,uplink througput,Downlink throughput
5025	          17104773,       247272821
9	 	  17104773,       247272821
38	 	  17104773,       247272821

What I have tried:
As of now only able to fetch expected output required from Input File 2:

with open("infile.txt") as infile, open("outfile.csv", "w") as outfile:
    data = infile.read()     #Read infile content
    ave_rate_from_user = re.search(r"ave rate from user\(bps\)\s*:\s*(\d+)\b", data)     #Search for `ave rate from user`
    if ave_rate_from_user:
        ave_rate_from_user = ave_rate_from_user.group(1)
    ave_rate_to_user = re.search(r"ave rate to user\(bps\)\s*:\s*(\d+)\b", data)  #Search for `ave rate to user`
    if ave_rate_to_user:
        ave_rate_to_user = ave_rate_to_user.group(1)

    writer = csv.writer(outfile)
    writer.writerow(["ave rate from user(bps)", "ave rate to user(bps)"])  #Write Header
    writer.writerow([ave_rate_from_user, ave_rate_to_user])    #Write Content