Android : Android changing color of Progress bar inner circle

I have a progress bar and a textview

My progressbar.xml looks like

   <?xml version="1.0" encoding="utf-8"?>
   <shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:innerRadiusRatio="3"
       android:shape="ring"
       android:thicknessRatio="7.0">
       <gradient
             android:centerColor="#007DD6"
             android:endColor="#FF000F"
             android:startColor="#007DD6"
             android:angle="90"
             android:type="sweep"
             android:useLevel="false" />
   </shape>

My layout is:

   <RelativeLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center">
        <ProgressBar
            android:id="@+id/progressBar"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="60dp"
            android:layout_height="60dp"
            android:indeterminate="false"
            android:max="60"
            android:progressDrawable="@drawable/progressbar">
        </ProgressBar>
    <TextView
        android:id="@+id/progresstext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:background="@android:color/transparent"
        android:gravity="center" />
</RelativeLayout>

    one more frame layout after this

I have a countdown of 60 seconds and i show that in progresstext. What i want to do is whenever the count down reaches 45 seconds, i want to change the color of inner circle to red(or any color for that matter) to indicate the user about the time.

I have tried changing the background color of textview but it did not cover the whole inner circle. Is there any way to change the color of the inner circle???

Thank you :)